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Jeremy Keith notes that what happens between the breakpoints is just as important as the breakpoints themselves—perhaps even more so. While I agree with this, we do have to start somewhere. In a way, this part of the process reminds me of storyboarding, or creating animation keyframes, with the in-between frames being developed later. We’re going to do that here.

Major breakpoints are conditions that, when met, trigger major changes in your design. A major breakpoint might be, for example, where your entire layout must change from two columns to four.

Let’s say you’ve chosen three basic design directions from your thumbnails. Think about what your major breakpoints will look like (Figure 7.6). And here’s the key: try to come up with as few major breakpoints as possible. That might sound crazy, since we’re talking about responsive design. After all, we have media queries, so let’s use about 12 of them, right? No! If a linear layout works for every screen and is appropriate for your particular concept, then there’s no need for different layouts. In that case, simply describe what will happen when the screen gets larger. Will everything generally stay the same, with changes only to font size, line height and margins? If so, sketch those. For these variations, make thumbnails first, explore some options, and then move on to larger, more detailed sketches. Use your breakpoint graph as a guide at first and make sketches according to the breakpoints you’ve estimated on your graph.

When thinking about major breakpoints, remember to think about device classes. If you’re thinking about smartphones, tablets, laptops/desktops, TVs, and game consoles, for example, you’re heading in the right direction. If you’re thinking in terms of brand names and specific operating systems, you’re on the wrong track. The idea is to think in terms of general device classifications and, sometimes, device capabilities. Capabilities are more important when designing web applications, since you should be thinking about what screens will look like both with and without any particular capability.

Rough sketches of major breakpoints can help you determine:

Rough sketches are more detailed than thumbnails, but they shouldn’t take a long time to create. In a short period, you should have a sketch of each major breakpoint for each of your chosen designs. This should be enough to decide on one of the designs.

  • Whether or not more major breakpoints are needed
  • Which design choice will be the most labor intensive; you might opt for a design that will better fit within time and budget constraints
  • Whether or not a particular device class has been neglected or needs further consideration
  • What technologies you’ll need to develop the design responsively


Figure 7.6: Most websites need very few major breakpoints.

Minor breakpoints are conditions that, when met, trigger small changes in your design. An example would be moving form labels from above text fields to the left of those fields, while the rest of the design remains the same.

So where and when will you sketch minor breakpoints? In the browser, when you do your web-based mockup. You’ll find out why and how in the next chapter. In the meantime, simply focus on making sketches of the state of your web pages or app screens at the major breakpoints of each design.

At this point, don’t worry too much if you notice that the initial breakpoints on your breakpoint graph simply won’t do. Those were just a starting point, and you’re free to revise your estimate based on your sketches. You might even decide that you need an extra breakpoint for a given design and record that in sketch form; you can add that breakpoint to your graph. This is a cycle of discovery, learning, and revision.

Think about your content while sketching

While sketching, you’ll certainly be thinking about the way things should look. My experience is that much UI sketching of this type revolves around the layout of elements on the screen. I’ve found it useful to keep thinking about the content while sketching, and to consider what will happen to the content in various situations. When designing responsively, it can be useful to consider how you’ll handle the following content in particular:

  • Text
  • Navigation
  • Tables

Oh, sure, there are many more things to consider, and you’ll end up creating your own list of “things to do some extra thinking about” as the project progresses. For now, let’s take a look at the items listed above.

Text

Before you say, “Hey, wait a minute, didn’t you just tell me that I didn’t have to draw text while sketching?” hear me out. While sketching, there are a couple of text-related issues you’ll need to tackle: column width and text size, both of which are relevant in proportion to the screen and the other elements on the page.

Column width is fairly obvious, but it can be difficult to estimate how wide a column will be with actual text. In this case, sketching on a device might give you a better idea of the actual space you have to work with. Another method I’ve used is just to make a simple HTML page that contains only text, and load that into a device’s browser (or even an emulator, which while not optimal still gives a more realistic impression than lines on paper). When the text seems too large or too small, you can adjust the font size accordingly. Once it seems right, you’ll be able to make your sketches a bit more realistic.

Note: Distinguish between touchability and clickability. Many designers, myself included, have made the mistake of refining links for people who click on them using a mouse, or even via the keyboard, without considering how touchable these links are for people on touch devices.

Think about the size of links—not only the text size, but also the amount of space around them. Both of these factors play a role in the touchability or clickability of links (and buttons): large links and buttons are easier targets, but slightly smaller links with plenty of space around them can work just as well. That said, there’s a decent chance that no matter what you choose to sketch, you’ll end up making changes again when you create your mockups.

This is the great thing about sketching that I can’t repeat often enough: you’re going to refine your design in the browser anyway, so the speed with which you can try things out when sketching means you won’t have to do detail work more than once (unless your client has changes, but we all know that never happens).

Navigation

Navigation is another poster child for sketching on actual devices. The size issues are the same as with links, but there’s a lot more thinking to do in terms of the design of navigation for various devices, which means navigation might change significantly at each major breakpoint.

Think back to Bryan Rieger’s practice of designing in text first, and ponder what you would do before the very first breakpoint if you had only plain HTML and CSS at your disposal—in other words, if you had no JavaScript. That means no, you can’t have your menu collapsed at the top of the screen and have it drop down when someone touches it. If you have your menu at the top, it’s in its expanded form and takes up all the vertical space it normally would.

This is a controversial enough subject, with even accessibility gurus in disagreement: JavaScript, after all, is currently considered an “accessibility supported” technology. But this isn’t necessarily about accessibility. It’s about thinking about what happens when a browser lacks JavaScript support, or if the JavaScript available on the device is different than what you’d expect. Your content will be presented in a certain way before JavaScript does its thing with it, no matter what the browser. So why not think about what that initial state will be?

In the chapter on wireframes, I talked about my preferred pattern for navigation on the smallest screens: keep it near the bottom of the screen and place a link to that navigation near the top of the screen. JavaScript, when available and working as expected, can move that navigation up to the top and create the drop-down menu on the fly.

But a pattern is not design law, so how you choose to handle the smallest screens will depend on your project. If I had only a few links in my navigation, I might very well put the menu at the top from the very start, and there it would stay at every breakpoint.

Remember that JavaScript and CSS let you do a lot of rearranging of stuff on the screen. That knowledge should empower you to safely design a great page with plain HTML and use JavaScript and CSS to spice it up any way you like. This is the essence of progressive enhancement.

Tables

Tables! Oh, the bane of the responsive designer (or wait, is that images? Or video? Or layout? Ahem). Tables are tough to deal with on small screens. I’d love to tell you I have all the answers, but instead I have more questions. Hopefully, these will lead you to a solution. It’s good to think about these while you’re sketching.

First of all, what types of tables will you be dealing with? Narrow? Wide? Numerical? Textual? Your content inventory should give you enough information to answer these simple questions. Once you’ve considered those, try to categorize the types of tables you have into something like the following classes (Figure 7.7):

  • Small-screen-friendly tables, which you’ll probably leave as they are, because they’re small enough and will work fine on most small screens.
  • Blockable tables, which you can alter with CSS so that each row in the table functions visually as a block item in a list (Figure 7.8).
  • Chartable tables, which contain numerical data that can be transformed into a chart, graph, or other visualization that will take up less space on a small screen.
  • Difficult tables, which are hard enough to deal with that you’ll need to come up with a different plan for them, sometimes even on a case-by-case basis. These are our enemies, but unfortunately, are the friends of our clients, who all love Microsoft Excel. Oh well.


Figure 7.7: There are several different types of tables, and different ways of dealing with them on small screens. (Sources: mobilism.nl and eu-verantwoording.nl)


Figure 7.8: One way of dealing with small screen tables is to treat each row as a block.

Thinking again in terms of progressive enhancement, the base design should probably just include the whole table, which means that the user will have to scroll horizontally to see the whole thing in many cases. On top of this, we can employ CSS and JavaScript, when they’re available, to do some magic for us. Blockable and chartable tables can be blocked with CSS and charted with JavaScript. Plenty of designers and developers have experimented with many different options for tables, from simply making the table itself scrollable to exchanging columns and rows.

The fun part is that what you do on small screens isn’t necessarily what you’ll do on larger screens. That’s why now—when all you have to do is sketch and it won’t take much time—is the time to think about the changes you’ll be making at each breakpoint.

What to do if you get stuck

Every designer gets stuck at some point. It’s no big deal unless you treat it like one. There are countless ways to deal with it, from asking yourself what if questions (“What if it weren’t a table, but a list?” is what I asked myself before “blockifying” the attendees table for the Mobilism site) to the cliché taking a shower, which you hopefully do on a regular basis anyway. The reason this chapter focuses so much on sketching is because the act of drawing itself can actually stimulate your brain to come up with more ideas, provided you push it hard enough by sketching past your comfort zone of first-come ideas.

If your problem is that you’re stuck creatively, there are many inspiring books and resources to get your creative engine started during the bitter cold of designer’s block. Although there are plenty of resources on design and creativity itself (try such classics as Edward de Bono’s Lateral Thinking), the greatest inspiration can come from sources outside the realm of design.1 Trying to combine things that normally aren’t combined can lead to surprising results. It’s a simple little trick, but I’ve often used Brian Eno and Peter Schmidt’s Oblique Strategies to force me to take a different approach.2 Worst case, it’s a lot of fun. Best case, you’ve got a great idea!

If your problem is that you’re not sure how to handle something in the context of responsive design, there’s no harm in researching how others have solved problems like yours. Just be sure to use your creativity and tailor any ideas you might find to your own situation; after all, you’re a designer. At the time of this writing I find Brad Frost’s This Is Responsive to be one of the most exhaustive collections of responsive design patterns and resources available.3 You can spend hours going through there and you’ll certainly come across something that will get you unstuck.

Excerpted from Responsive Design Workflow by Stephen Hay. Copyright © 2013.
Used with permission of Pearson Education, Inc. and New Riders.

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Three years ago in these pages, ALA technical editor Ethan Marcotte fired the shot heard ’round the web. ALA designer Mike Pick thought it might be fun to celebrate the third anniversary of “Responsive Web Design” (A List Apart Issue No. 306, May 25, 2010) by secreting an Easter Egg in the original article; our illustrator, Kevin Cornell, rose to the challenge.

To see it in action, visit alistapart.com/article/responsive-web-design, grab the edge of the browser window (device permitting), and perform the responsive resize mambo. (ALA’s Tim Murtaugh, who coded the Easter Egg, has provided a handy video demo of what you’ll see.)

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Responsive Web design has been around for some years now, and it was a hot topic in 2012. Many well-known people such as Brad Frost and Luke Wroblewski have a lot of experience with it and have helped us make huge improvements in the field. But there’s still a whole lot to do.

In this article, we will look at what is currently possible, what will be possible in the future using what are not yet standardized properties (such as CSS Level 4 and HTML5 APIS), and what still needs to be improved. This article is not exhaustive, and we won’t go deep into each technique, but you’ll have enough links and knowledge to explore further by yourself.

The State Of Images In Responsive Web Design

What better aspect of responsive Web design to start off with than images? This has been a major topic for a little while now. It got more and more important with the arrival of all of the high-density screens. By high density, I mean screens with a pixel ratio higher than 2; Apple calls these Retina devices, and Google calls them XHDPI. In responsive Web design, images come with two big related challenges: size and performance.

Most designers like pixel perfection, but “normal”-sized images on high-density devices look pixelated and blurry. Simply serving double-sized images to high-density devices might be tempting, right? But that would create a performance problem. Double-sized images would take more time to load. Users of high-density devices might not have the bandwidth necessary to download those images. Also, depending on which country the user lives in, bandwidth can be pretty costly.

The second problem affects smaller devices: why should a mobile device have to download a 750-pixel image when it only needs a 300-pixel one? And do we have a way to crop images so that small-device users can focus on what is important in them?

Two Markup Solutions: The <picture> Element and The srcset Attribute

A first step in solving the challenge of responsive images is to change the markup of embedded images on an HTML page.

The Responsive Images Community Group supports a proposal for a new, more flexible element, the <picture> element. The concept is to use the now well-known media queries to serve different images to different devices. Thus, smaller devices would get smaller images. It works a bit like the markup for video, but with different images being referred to in the source element.

The code in the proposed specification looks like this :


<picture width="500"  height="500">     
  <source  media="(min-width: 45em)" src="large.jpg">
  <source  media="(min-width: 18em)" src="med.jpg">
  <source  src="small.jpg">
  <img  src="small.jpg" alt="">
  <p>Accessible  text</p>
</picture>

If providing different sources is possible, then we could also imagine providing different crops of an image to focus on what’s important for smaller devices. The W3C’s “Art Direction” use case shows a nice example of what could be done.

Picture element used for artistic direction
(Image: Egor Pasko)

The solution is currently being discussed by the W3C Responsive Images Community Group but is not usable in any browser at the moment as far as we know. A polyfill named Picturefill is available, which does pretty much the same thing. It uses a div and data-attribute syntax for safety’s sake.

A second proposal for responsive images markup was made to the W3C by Apple and is called “The srcset Attribute”; its CSS Level 4 equivalent is image-set(). The purpose of this attribute is to force user agents to select an appropriate resource from a set, rather than fetch the entire set. The HTML syntax for this proposal is based on the <img> tag itself, and the example in the specification looks like this:


<img  alt="The Breakfast Combo" 
  src="banner.jpeg"
  srcset="banner-HD.jpeg  2x, banner-phone.jpeg 100w, banner-phone-HD.jpeg 100w 2x">

As you can see, the syntax is not intuitive at all. The values of the tag consist of comma-separated strings. The values of the attribute are the names or URLs of the various images, the pixel density of the device and the maximum viewport size each is intended for.

In plain English, this is what the snippet above says:

  • The default image is banner.jpeg.
  • Devices that have a pixel ratio higher than 2 should use banner-HD.jpeg.
  • Devices with a maximum viewport size of 100w should use banner-phone.jpeg.
  • Devices with a maximum viewport size of 100w and a pixel ratio higher than 2 should use banner-phone-HD.jpeg.

The first source is the default image if the srcset attribute is not supported. The 2x suffix for banner-HD.jpeg means that this particular image should be used for devices with a pixel ratio higher than 2. The 100w for banner-phone.jpeg represents the minimum viewport size that this image should be used for. Due to its technical complexity, this syntax has not yet been implemented in any browser.

The syntax of the image-set() CSS property works pretty much the same way and enables you to load a particular background image based on the screen’s resolution:


background-image: image-set(  "foo.png" 1x,
  "foo-2x.png"  2x,
  "foo-print.png"  600dpi );

This proposal is still a W3C Editor’s Draft. For now, it works in Safari 6+ and Chrome 21+.

Image Format, Compression, SVG: Changing How We Work With Images on the Web

As you can see, these attempts to find a new markup format for images are still highly experimental. This raises the issue of image formats themselves. Can we devise a responsive solution by changing the way we handle the images themselves?

The first step would be to look at alternative image formats that have a better compression rate. Google, for example, has developed a new image format named WebP, which is 26% smaller than PNG and 25 to 34% smaller than JPEG. The format is supported in Google Chrome, Opera, Yandex, Android and Safari and can be activated in Internet Explorer using the Google Chrome Frame plugin. The main problem with this format is that Firefox does not plan to implement it. Knowing this, widespread use is unlikely for now.

Another idea that is gaining popularity is progressive JPEG images. Progressive JPEG images are, as the name suggests, progressively rendered. The first rendering is blurry, and then the image gets progressively sharper as it renders. Non-progressive JPEG images are rendered from top to bottom. In her article “Progressive JPEGs: A New Best Practice,” Ann Robson argues that progressive JPEGs give the impression of greater speed than baseline JPEGs. A progressive JPEG gives the user a quick general impression of the image before it has fully loaded. This does not solve the technical problems of performance and image size, though, but it does improve the user experience.

Another solution to the problems of performance and image size is to change the compression rate of images. For a long time, we thought that enlarging the compression rate of an image would damage the overall quality of the image. But Daan Jobsis has done extensive research on the subject and has written an article about it, “Retina Revolution.” In his experiments, he tried different image sizes and compression rates and came up with a pretty interesting solution. If you keep the image dimensions twice the displayed ones but also use a higher compression rate, then the image will have a smaller file size than the original, but will still be sharp on both normal and high-density screens. With this technique, Jobsis cut the weight of the image by 75%.

Image compression example
Daan Jobsis’ demonstration of image compression.

Given the headaches of responsive images, the idea of gaining pixel independence from images wherever possible is seducing more and more designers and developers. The SVG format, for example, can be used to create all of the UI elements of a website and will be resolution-independent. The elements will scale well for small devices and won’t be pixellated on high-density devices. Font icons are another growing trend. They involve asigning icon glyphs to certains characters of the font (like the Unicode Private Area ones), giving you the flexibility of fonts. Unfortunately, the solution doesn’t work with pictures, so a viable markup or image format is eagerly expected.

Responsive Layout Challenge: Rearrange And Work With Content Without Touching the HTML?

Let’s face it, the fluid grids made of floats and inline blocks that we use today are a poor patch waiting for a better solution. Working with layout and completely rearranging blocks on the page for mobile without resorting to JavaScript is a nightmare right now. It’s also pretty inflexible. This is particularly significant on websites created with a CMS; the designer can’t change the HTML of every page and every version of the website. So, how can this be improved?

Four CSS3 Layout Solutions That Address the Flexible Layout Problem

The most obvious possible solution is the CSS3 flexible box layout model (or “flexbox”). Its current status is candidate recommendation, and it is supported in most major mobile browsers and desktop browsers (in IE starting from version 10). The model enables you to easily reorder elements on the screen, independent of the HTML. You can also change the box orientation and box flow and distribute space and align according to the context. Below is an example of a layout that could be rearranged for mobile. The syntax would look like this:


.parent {
  display: flex;
  flex-flow: column; /* display items in columns */
}

.children {
  order: 1; /* change order of elements */
}

Flexbox as an example

The article “CSS3 Flexible Box Layout Explained” will give you a deeper understanding of how flexbox works.

Another solution quite close to the flexbox concept of reordering blocks on the page, but with JavaScript, is Relocate.

A second type of layout that is quite usable for responsive design today is the CSS3 multiple-column layout. The module is at the stage of candidate recommendation, and it works pretty well in most browsers, expect for IE 9 and below. The main benefit of this model is that content can flow from one column to another, providing a huge gain in flexibility. In terms of responsiveness, the number of columns can be changed according to the viewport’s size.

Setting the size of the columns and letting the browser calculate the number of columns according to the available space is possible. Also possible is setting the number of columns, with the gaps and rules between them, and letting the browser calculate the width of each column.

CSS3 Multiple Column layout

The syntax looks like this:


.container {
  column-width: 10em ; /* Browser will create 10em columns. Number of columns would depend on available space. */
}

.container {
  columns: 5; /* Browser will create 5 columns. Column size depends on available space. */
  column-gap: 2em;
}

To learn more, read David Walsh’s article “CSS Columns.”

A third CSS3 property that could gain more attention in future is the CSS3 grid layout. This gives designers and developers a flexible grid they can work with to create different layouts. It allows content elements to be displayed in columns and rows without a defined structure. First, you would declare a grid on the container, and then place all child elements in this virtual grid. You could then define a different grid for small devices or change the position of elements in the grid. This allows for enormous flexibility when used with media queries, changes in orientation and so on.

The syntax looks like this (from the 2 April 2013 working draft):


 .parent {
   display: grid; /* declare a grid */
   grid-definition-columns: 1stgridsize  2ndgridsize …;
   grid-definition-rows: 1strowsize  2ndrowsize …;
}

.element {
   grid-column: 1; 
   grid-row: 1
}

.element2 {
   grid-column: 1; 
   grid-row: 3;
}

To set the sizes of columns and rows, you can use various units, as detailed in the specification. To position the various elements, the specification says this: “Each part of the game is positioned between grid lines by referencing the starting grid line and then specifying, if more than one, the number of rows or columns spanned to determine the ending grid line, which establishes bounds for the part.”

The main problem with this property is that it is currently supported only in IE 10. To learn more about this layout, read Rachel Andrew’s “Giving Content Priority With CSS3 Grid Layout.” Also, note that the specification and syntax for grid layouts changed on 2 April 2013. Rachel wrote an update on the syntax, titled “CSS Grid Layout: What Has Changed?

The last layout that might become useful in future if implemented in browsers is the CSS3 template layout. This CSS3 module works by associating an element with a layout “name” and then ordering the elements on an invisible grid. The grid may be fixed or flexible and can be changed according to the viewport’s size.

The syntax looks like this:


.parent {
   display: "ab"
            "cd" /* creating the invisible  grid */
}

.child1 {
   position: a;
}

.child2 {
   position: b;
}

.child3 {
   position: c;
}

.child4 {
   position: d;
} 

This renders as follows:

CSS3 template layout

Unfortunately, browser support for this CSS3 module is currently null. Maybe someday, if designers and developers show enough interest in this specification, some browser vendors might implement it. For the moment, you can test it out with a polyfill.

Viewport-Relative Units and the End of Pixel-Based Layout

Viewport-based percentage lengths — vw, vh, vm, vmin and vmax — are units measured relative to the dimensions of the viewport itself.

One vw unit is equal to 1% of the width of the initial containing block. If the viewport’s width is 320, then 1 vw is 1 × 320/100 = 3.2 pixels.

The vh unit works the same way but is relative to the height of the viewport. So, 50 vh would equal 50% of the height of the document. At this point, you might wonder what the difference is with the percentage unit. While percentage units are relative to the size of the parent element, the vh and vw units will always be relative to the size of the viewport, regardless of the size of their parents.

This gets pretty interesting when you want to, for example, create a content box and make sure that it never extends below the viewport’s height so that the user doesn’t have to scroll to find it. This also enables us to create true 100%-height boxes without having to hack all of the elements’ parents.

The vmin unit is equal to the smaller of vm or vh, and vmax is equal to the larger of vm or vh; so, those units respond perfectly to changes in device orientation, too. Unfortunately, for the moment, those units are not supported in Android’s browser, so you might have to wait a bit before using them in a layout.

A Word on Adaptive Typography

The layout of a website will depend heavily on the content. I cannot conclude a section about the possibilities of responsive layout without addressing typography. CSS3 introduces a font unit that can be pretty handy for responsive typography: the rem unit. While fonts measured in em units have a length relative to their parent, font measured in rem units are relative to the font size of the root element. For a responsive website, you could write some CSS like the following and then change all font sizes simply by changing the font size specified for the html element:


html {
   font-size: 14px;
}

p {
   font-size: 1rem /* this has 14px */
}

@media screen and (max-width:380px) {
   html {
      font-size: 12px; /* make the font smaller for mobile devices */
   }

   p {
      font-size: 1rem /* this now equals 12px */
   }
}

Except for IE 8 and Opera mini, support for rem is pretty good. To learn more about rem units, read Matthew Lettini’s article “In Defense of Rem Units.”

A Better Way To Work Responsively With Other Complex Content

We are slowly getting better at dealing with images and text in responsive layouts, but we still need to find solutions for other, more complex types of content.

Dealing With Forms on a Responsive Website

Generally speaking, dealing with forms, especially long ones, in responsive Web design is quite a challenge! The longer the form, the more complicated it is to adapt to small devices. The physical adaptation is not that hard; most designers will simply put the form’s elements into a single column and stretch the inputs to the full width of the screen. But making forms visually appealing isn’t enough; we have to make them easy to use on mobile, too.

For starters, Luke Wroblewski advises to avoid textual input and instead to rely on checkboxes, radio buttons and select drop-down menus wherever possible. This way, the user has to enter as little information as possible. Another tip is not to make the user press the “Send” button before getting feedback about the content of their submission. On-the-fly error-checking is especially important on mobile, where most forms are longer than the height of the screen. If the user has mistyped in a field and has to send the form to realize it, then chances are they won’t even see where they mistyped.

In the future, the new HTML5 form inputs and attributes will be a great help to us in building better forms, without the need for (much) JavaScript. For instance, you could use the required attribute to give feedback about a particular field on the fly. Unfortunately, support for this on mobile devices is poor right now. The autocomplete attribute could also help to make forms more responsive.

A mobile phone is a personal possession, so we can assume that data such as name and postal address will remain consistent. Using the autocomplete HTML5 attribute, we could prefill such fields so that the user doesn’t have to type all of that information over and over. There is also a whole list of new HTML5 inputs that can be used in the near future to make forms more responsive.

Dates in form elements are a good example of what can be improved with HTML5. We used to rely on JavaScripts to create date-pickers. Those pickers are quite usable on big desktop screens but very hard to use on touch devices. Selecting the right date with a finger is difficult when the touch zones are so small.

Different picker examples
How am I supposed to select a date when my finger is touching three dates at the same time?

A promising solution lies in the new HTML5 input type="date", which sets a string in the format of a date. The HTML5 input type="datetime" sets a string in the format of a date and time. The big advantage of this method is that we let the browser decide which UI to use. This way, the UI is automatically optimized for mobile phones. Here is what an input type="date" looks like on the desktop, on an Android phone and tablet (with the Chrome browser), and on the iPhone and iPad.

Mobile input type=date rendering
Renderings of input type="date" on different mobile devices.

Note that the screenshots were taken in my browser and on the Android phone, so the language automatically adapted to the system language (French). By using native components, you no longer have to adapt the language into different versions of the website.

For now, support for input type="date" on the desktop is absent except in Opera and Chrome. Native Android browsers don’t support it at all, but Chrome for Android does, and so does Safari on iOS. A lot still has to get done in order for us to be able to use this solution on responsive websites. Meanwhile, you could use a polyfill such as Mobiscroll for mobile browsers that don’t support it natively.

Apart from these HTML5 input solutions, attempts have been made to improve other design patterns, such as passwords on mobile and complex input formatting using masks. As you will notice, these are experimental. The perfect responsive form does not exist at the moment; a lot still has to be done in this field.

Dealing With Tables on a Responsive Website

Another content type that gets pretty messy on mobile and responsive websites is tables. Most table are oriented horizontally and present a lot of data at once, so you can see how getting it right on a small screen is pretty hard. HTML tables are fairly flexible — you can use percentages to change the width of the columns — but then the content can quickly become unreadable.

No one has yet found the perfect way to present tables, but some suggestions have been made.

One approach is to hide what could be considered “less important” columns, and provide checkboxes for the user to choose which columns to see. On the desktop, all columns would be shown, while on mobile, the number of columns shown would depend on the screen’s size. The Filament Group explains this approach and demonstrates it in one of its articles. The solution is also used in the table column toggle on jQuery Mobile.

Responsive table examples
Some examples of responsive tables.

A second approach plays with the idea of a scrollable table. You would “pin” a single fixed-size column on the left and then leave a scroll bar on a smaller part of the table to the right. David Bushell implements this idea in an article, using CSS to display all of the content in the <thead> on the left side of the table, leaving the user to scroll through the content on the right. Zurb uses the same idea but in a different way for its plugin. In this case, the headers stay at the top of the table, and the table is duplicated with JavaScript so that only the first column is shown on the left, and all other columns are shown on the right with a scroll bar.

Responsive table overflow example
Two examples of scrollable responsive tables

The big issue with scroll bars and CSS properties such as overflow: auto is that many mobile devices and tablets simply won’t display a visible scroll bar. The right area of the table will be scrollable, but the user will have no visual clue that that’s possible. We have to find some way to indicate that more content lies to the right.

A third approach is to reflow a large table and split up the columns into what essentially looks like list items with headings. This technique is used in the “reflow mode” on jQuery Mobile and was explained by Chris Coyier in his article “Responsive Data Tables.”

Responsive table reflow example
Reflowing a table responsively

Many other techniques exist. Which to use depends heavily on your project. No two projects are the same, so I can only show you how other people have dealt with it. If you come up with a nice solution of your own, please share it with the world in the comments below, on Twitter or elsewhere. We are in this boat together, and tables suck on mobile, really, so let’s improve them together!

Embedding Third-Party Content: The Responsive Iframe Problem

Many websites consist of embedded third-party content: YouTube or Vimeo videos, SlideShare presentations, Facebook applications, Twitter feeds, Google Maps and so on. A lot of those third parties make you use iframes to embed their content. But let’s face it: iframes are a pain to deal with in responsive design. The big problem is that iframes force a fixed width and height directly in your HTML code. Forcing a 100% width on the iframe would work, but then you would lose the ratio of the embedded content. To embed a video or slideshow and preserve the original ratio, you would have to find a workaround.

An HTML and CSS Workaround

Thierry Koblentz has written a good article titled “Creating Intrinsic Ratios for Video,” in which he proposes a way to embed responsive videos using a 16:9 ratio. This solution can be extended to other sorts of iframe content, such as SlideShare presentations and Google Maps. Koblentz wraps the iframe in a container with a class that we can target in CSS. The container makes it possible for the iframe to resize fluidly, even if the iframe has fixed pixel values in the HTML. The code, adapted by Anders M. Andersen, looks like this:


 .embed-container  {
   position: relative;
   padding-bottom: 56.25%; /* 16:9 ratio */
   padding-top: 30px; /* IE 6 workaround*/
   height: 0;
   overflow: hidden;
}

.embed-container iframe,
.embed-container object,
.embed-container embed {
   position: absolute;
   top: 0;
   left: 0;
   width: 100%;
   height: 100%;
}

This will work for all iframes. The only potential problem is that you will have to wrap all of the iframes on your website in a <div class="embed-container"> element. While this would work for developers who have total control over their code or for clients who are reasonably comfortable with HTML, it wouldn’t work for clients who have no technical skill. You could, of course, use some JavaScript to detect iframe elements and automatically embed them in the class. But as you can see, it’s still a major workaround and not a perfect solution.

Dealing With Responsive Video In Future

HTML5 opens a world of possibilities for video — particularly with the video element. The great news is that support for this element is amazingly good for mobile devices! Except for Opera Mini, most major browsers support it. The video element is also pretty flexible. Presenting a responsive video is as simple as this:


video {
   max-width: 100%;
   height: auto;
}

You’re probably asking, “What’s the problem, then?”

The problem is that, even though YouTube or Vimeo may support the video element, you still have to embed videos using the ugly iframe method. And that, my friend, sucks. Until YouTube and Vimeo provide a way to embed videos on websites using the HTML5 video tag, we have to find workarounds to make video embedding work on responsive websites. Chris Coyier created such a workaround as a jQuery plugin called FitVids.js. It uses the first technique mentioned above: creating a wrapper around the iframe to preserve the ratio.

Embedding Google Maps

If you embed a Google Map on your website, the technique described above with the container and CSS will work. But, again, it’s a dirty little hack. Moreover, the map will resize in proportion and might get so tiny that the map loses the focus area that you wanted to show to the user. The Google Maps’ page for mobile says that you can use the static maps API for mobile embedding. Using a static map would indeed make the iframe problems go away. Brad Frost wrote a nice article about, and created a demo of, adaptive maps, which uses this same technique. A JavaScript detects the screen’s size, and then the iframe is replaced by the static map for mobile phones. As you can tell, we again have to resort to a trick to deal with the iframe problem, in the absence of a “native” solution (i.e. from Google).

We Need Better APIs

And now the big question: Is there a better way? The biggest problem with using iframes to embed third-party content responsively is the lack of control over the generated code. Developers and designers are severely dependent on the third party and, by extension, its generated HTML. The number of websites that provide content to other websites is growing quickly. We’ll need much better solutions than iframes to embed this content.

Let’s face it: embedding Facebook’s iframe is a real pain. The lack of control over the CSS can make our work look very sloppy and can even sometimes ruin the design. The Web is a very open place, so perhaps now would be a good time to start thinking about more open APIs! In the future, we will need APIs that are better and simpler to use, so that anyone can embed content flexibly, without relying on unresponsive fixed iframes. Until all of those very big third parties decide to create those APIs, we are stuck with sloppy iframes and will have to resort to tricks to make them workable.

Responsive Navigation: An Overview Of Current Solutions

Another big challenge is what to do with navigation. The more complex and deep the architecture of the website, the more inventive we have to be.

An early attempt to deal with this in a simple way was to convert the navigation into a dropdown menu for small screens. Unfortunately, this was not ideal. First, this solution gets terribly complicated with multiple-level navigation. It can also cause some problems with accessibility. I recommend “Stop Misusing Select Menus” to learn about all of the problems such a technique can create.

Some people, including Brad Frost and Luke Wroblewski, have attempted to solving this problem. Brad Frost compiled some of his techniques on the website This Is Responsive, under the navigation section.

Toggle navigation involves hiding the menu for small devices, displaying only a “menu” link. When the user clicks on it, all of the other links appear as block-level elements below it, pushing the main content below the navigation.

A variant of this, inspired by some native application patterns, is off-canvas navigation. The navigation is hidden beneath a “menu” link or icon. When the user clicks the link, the navigation slides out as a panel from the left or right, pushing the main content over.

Toggle navigation example
Some examples of toggle navigation

The problem with these techniques is that the navigation remains at the top of the screen. In his article “Responsive Navigation: Optimizing for Touch Across Devices,” Luke Wroblewski illustrates which zones are easily accessible for different device types. The top left is the hardest to get to on a mobile device.

Easy touch access for mobile and tablet
Easily accessible screen areas on mobile phones and tablets, according to Luke Wroblewski.

Based on this, Jason Weaver created some demos with navigation at the bottom. One solution is a footer anchor, with navigation put at the bottom of the page for small devices, and a “menu” link that sends users there. It uses the HTML anchor link system.

Many other attempts have been made to solve the navigation problem in responsive Web design. As you can see, there is not yet a perfect solution; it really depends on the project and the depth of the navigation. Fortunately for us, some of the people who have tried to crack this nut have shared their experiences with the community.

Another unsolved issue is what icon to use to tell the user, “Hey! There’s a menu hidden under me. Click me!” Some websites have a plus symbol (+), some have a grid of squares, other have what looks like an unordered list, and some have three lines (aka the burger icon).

Some responsive icons example
To see these icons used on real websites, have a look at “We Need a Standard ‘Show Navigation’ Icon for Responsive Web Design.”

The main problem is figuring out which of these icons would be the most recognizable to the average user. If we all agreed to use one of them, users would be trained to recognize it. The problem is which to choose? I really would like to know which icon you use, so don’t hesitate to share it in the comments below.

Mobile Specificities: “Is The User On A Mobile Device? If So, What Can It Do?”

Mobile and tablet devices are a whole new world, far removed from desktop computers, with their own rules, behaviors and capabilities. We might want to adapt our designs to this new range of capabilities.

Detecting Touch Capabilities With Native JavaScript

Apart from screen size, I bet if you asked what is the main difference between desktop and mobile (including tablets), most people would say touch capability. There is no mouse on a mobile phone (no kidding!), and except for some rare hybrid devices into which you can plug a mouse, you can’t do much with mouse events on a tablet. This means that, depending on the browser, the :hover CSS pseudo-class might not work. Some browsers are clever enough to provide a native fallback for the hover event by translating it into a touch event. Unfortunately, not all browsers are so flexible. Creating a design that doesn’t depend on hidden elements being revealed on :hover events would be wise.

Catching touch events could also be another solution. A W3C working group has started working on a touch event specification. In the future, we will be able to catch events such as touchstart, touchmove and toucheend. We will be able to deal with these events directly in JavaScript without requiring a third-party framework such as Hammer.js or jGestures. But JavaScript is one thing — what about CSS?

CSS Level 4 “Pointer” Media Query

CSS Level 4 specifies a new media query called “pointer”, which can be used to query the presence and accuracy of a pointing device, such as a mouse. The media query takes one of three values:

  • none
    The device does not have any pointing device at all.
  • coarse
    The device has a pointing device with limited accuracy; for example, a mobile phone or tablet with touch capabilities, where the “pointer” would be a finger.
  • fine
    The device has an accurate pointing device, such as a mouse, trackpad or stylus.

Using this media query, we can enlarge buttons and links for touch devices:


@media  (pointer:coarse) {
   input[type="submit"],
       a.button {
       min-width: 30px;
       min-height: 40px;
       background: transparent;
   }
 }

The pointer media query is not yet supported and is merely being proposed. Nevertheless, the potential is huge because it would enable us to detect touch devices via CSS, without the need for a third-party library, such as Modernizr.

CSS Level 4 “Hover” Media Query

The CSS Level 4 specification proposes a new hover media query, which detects whether a device’s primary pointing system can hover. It returns a Boolean: 1 if the device supports hover, 0 if not. Note that it has nothing to do with the :hover pseudo-class.

Using the hover media query, we can enhance an interface to hide certain features for devices that do support hovering. The code would look something like this:


 @media  (hover) {
   .hovercontent { display: none; } /* Hide content only for devices with hover capabilities. */

   .hovercontent:hover { display: block; }    
 }

It can also be used to create dropdown menus on hover; and the fallback for mobile devices is in native CSS, without the need for a feature-detection framework.

CSS Level 4 Luminosity Media Query

Another capability of mobile devices is the luminosity sensor. The CSS Level 4 specification has a media query for luminosity, which gives us access to a device’s light sensors directly in the CSS. Here is how the specification describes it:

“The “luminosity” media feature is used to query about the ambient luminosity in which the device is used, to allow the author to adjust style of the document in response.”

In the future, we will be able to create websites that respond to ambient luminosity. This will greatly improve user experiences. We will be able to detect, for example, exceptionally bright environments using the washed value, adapting the website’s contrast accordingly. The dim value is used for dim environments, such as at nighttime. The normal value is used when the luminosity level does not need any adjustment.

The code would look something like this:


 @media  (luminosity: washed) {
   p { background: white; color: black; font-size: 2em; }
 }

As you can see, CSS Level 4 promises a lot of fun new stuff. If you are curious to see what’s in store, not only mobile-related, then have a look at “Sneak Peek Into the Future: Selectors, Level 4.”

More Mobile Capabilities to Detect Using APIs and JavaScript

Many other things could be detected to make the user experience amazing on a responsive website. For example, we could gain access to the native gyroscope, compass and accelerometer to detect the device’s orientation using the HTML5 DeviceOrientationEvent. Support for DeviceOrientationEvent in Android and iOS browsers is getting better, but the specification is still a draft. Nevertheless, the API look promising. Imagine playing full HTML5 games directly in the browser.

Another API that would be particularly useful for some mobile users is geolocation. The good news is that it’s already well supported. This API enables us to geolocate the user using GPS and to infer their location from network signals such as IP address, RFID, Wi-Fi and Bluetooth MAC addresses. This can be used on some responsive websites to provide users with contextual information. A big restaurant chain could enhance its mobile experience by showing the user the locations of restaurants in their area. The possibilities are endless.

The W3C also proposed a draft for a vibration API. With it, the browser can provide tactile feedback to the user in the form of vibration. This, however, is creeping into the more specific field of Web applications and mobile games in the browser.

Another API that has been highly discussed is the network information API. The possibility of measuring a user’s bandwidth and optimizing accordingly has seduced many developers. We would be able to serve high-quality images to users with high bandwidth and low-quality images to users with low bandwidth. With the bandwidth attribute of the network API, it would be possible to estimate the downloading bandwidth of a user in megabytes per second. The second attribute, metered, is a Boolean that tells us whether the user has a metered connection (such as from a prepaid card). These two attributes are currently accessible only via JavaScript.

Unfortunately, measuring a user’s connection is technically difficult, and a connection could change abruptly. A user could go into a tunnel and lose their connection, or their speed could suddenly drop. So, a magical media query that measures bandwidth looks hypothetical at the moment. Yoav Weiss has written a good article about the problems that such a media query would create and about bandwidth measurement, “Bandwidth Media Queries? We Don’t Need ’Em!

Many other APIs deal with mobile capabilities. If you are interested in learning more, Mozilla has a very detailed list. Most are not yet fully available or standardized, and most are intended more for Web applications than for responsive websites. Nevertheless, it’s a great overview of how large and complex mobile websites could get in future.

Rethinking The Way We And The User Deal With Content

From a technical perspective, there are still a lot of challenges in dealing with content at a global scale. The mobile-first method has been part of the development and design process for a little while now. We could, for example, serve to mobile devices the minimum data that is necessary, and then use JavaScript and AJAX to conditionally load more content and images for desktops and tablets. But to do this, we would also have to rethink how we deal with content and be able to prioritize in order to generate content that is flexible enough and adaptive. A good example of this is the responsive map solution described above: we load an image for mobile, and enhance the experience with a real map for desktops. The more responsive the website, the more complex dealing with content gets. Flexible code can help us to format adaptive content.

One way suggested by some people in the industry is to create responsive sentences by marking up sentences with a lot of spans that have classes, and then displaying certain ones according to screen size. Trimming parts of sentences for small devices is possible with media queries. You can see this technique in action on 37signals’ Signal vs. Noise blog and in Frankie Roberto’s article “Responsive Text.” Even if such technique could be used to enhance small parts of a website, such as the footer slogan, applying it to all of the text on a website is hard to imagine.

This raises an issue in responsive Web design that will become more and more important in future: the importance of meta data and the semantic structure of content. As mentioned, the content on our websites does not only come from in-house writers. If we want to be able to automatically reuse content from other websites, then it has to be well structured and prepared for it. New HTML5 tags such as article and section are a good start to gaining some semantic meaning. The point is to think about and structure content so that a single item (say, a blog post) can be reused and displayed on different devices in different formats.

The big challenge will be to make meta data easily understandable to all of the people who are part of the content creation chain of the website. We’ll have to explain to them how the meta data can be used to prioritize content and be used to programmatically assemble content, while being platform-independent. A huge challenge will be to help them start thinking in terms of reusable blocks, rather than a big chunk of text that they copy and paste from Microsoft Word to their WYSIWYG content management system. We will have to help them understand that content and structure are two separate and independent things, just as when designers had to understand that content (HTML) and presentation (CSS) are best kept separate.

We can’t afford to write content that is oriented towards one only platform anymore. Who knows on which devices our content will be published in six months, or one year? We need to prepare our websites for the unexpected. But to do so, we need better publishing tools, too. Karen McGrane gave a talk on “Adapting Ourselves to Adaptive Content,” with some real example from the publishing industry. She speaks about the process of creating reusable content and introduces the idea of COPE: create once and publish everywhere. We need to build better CMSes, ones that can use and generate meta data to prioritize content. We need to explain to people how the system works and to think in terms of modular reusable content objects, instead of WYSIWYG pages. As McGrane says:

“You might be writing three different versions of that headline; you might be writing two different short summaries and you are attaching a couple of different images to it, different cut sizes, and then you may not be the person who is in charge of deciding what image or what headline gets displayed on that particular platform. That decision will be made by the metadata. It will be made by the business rules. […] Metadata is the new art direction.”

Truncating content for small devices is not a future-proof content strategy. We need CMSes that provide the structure needed to create such reusable content. We need better publishing workflows in CMSes, too. Clunky interfaces scare users, and most people who create content are not particularly comfortable with complicated tools. We will have to provide them with tools that are easy to understand and that help them publish clean, semantic content that is independent of presentation.

Conclusion

As long as this article is, it only scratches the surface. By now, most of Smashing Magazine’s readers understand that responsive Web design is much more than about throwing a bunch of media queries on the page, choosing the right breakpoints and doubling the size of images for those cool new high-density phones. As you can see, the path is long, and we are not there yet. There are still many unsolved issues, and the perfect responsive solution does not exist yet.

Some technical solutions might be discovered in future using some of the new technologies presented here and with the help of the W3C, the WHATWG and organizations such as the Filament Group.

More importantly, we Web designers and developers can help to find even better solutions. People such as Luke Wroblewski and Brad Frost and all of the amazing women and men mentioned in this article are experimenting with a lot of different techniques and solutions. Whether any succeeds or fails, the most important thing is to share what we — as designers, developers, content strategists and members of the Web design community — are doing to try to solve some of the challenges of responsive Web design. After all, we are all in the same boat, trying to make the Web a better place, aren’t we?

(al) (ea)

© Stéphanie Walter for Smashing Magazine, 2013.

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Original author: 
David Storey

  

Flexible box layout (or flexbox) is a new box model optimized for UI layout. As one of the first CSS modules designed for actual layout (floats were really meant mostly for things such as wrapping text around images), it makes a lot of tasks much easier, or even possible at all. Flexbox’s repertoire includes the simple centering of elements (both horizontally and vertically), the expansion and contraction of elements to fill available space, and source-code independent layout, among others abilities.

Flexbox has lived a storied existence. It started as a feature of Mozilla’s XUL, where it was used to lay out application UI, such as the toolbars in Firefox, and it has since been rewritten multiple times. The specification has only recently reached stability, and we have fairly complete support across the latest versions of the leading browsers.

There are, however, some caveats. The specification changed between the implementation in Internet Explorer (IE) and the release of IE 10, so you will need to use a slightly different syntax. Chrome currently still requires the -webkit- prefix, and Firefox and Safari are still on the much older syntax. Firefox has updated to the latest specification, but that implementation is currently behind a runtime flag until it is considered stable and bug-free enough to be turned on by default. Until then, Firefox still requires the old syntax.

When you specify that an element will use the flexbox model, its children are laid out along either the horizontal or vertical axis, depending on the direction specified. The widths of these children expand or contract to fill the available space, based on the flexible length they are assigned.

Example: Horizontal And Vertical Centering (Or The Holy Grail Of Web Design)

Being able to center an element on the page is perhaps the number one wish among Web designers — yes, probably even higher than gaining the highly prized parent selector or putting IE 6 out of its misery (OK, maybe a close second then). With flexbox, this is trivially easy. Let’s start with a basic HTML template, with a heading that we want to center. Eventually, once we’ve added all the styling, it will end up looking like this vertically and horizontally centered demo.


<!DOCTYPE html>
<html lang="en">
<head>
   <meta charset="utf-8"/>
   <title>Centering an Element on the Page</title>
</head>
<body>
   <h1>OMG, I’m centered</h1>
</body>
</html>

Nothing special here, not even a wrapper div. The magic all happens in the CSS:


html {
   height: 100%;
} 

body {
   display: -webkit-box;   /* OLD: Safari,  iOS, Android browser, older WebKit browsers.  */
   display: -moz-box;   /* OLD: Firefox (buggy) */ 
   display: -ms-flexbox;   /* MID: IE 10 */
   display: -webkit-flex;    /* NEW, Chrome 21+ */
   display: flex;       /* NEW: Opera 12.1, Firefox 22+ */

   -webkit-box-align: center; -moz-box-align: center; /* OLD… */
   -ms-flex-align: center; /* You know the drill now… */
   -webkit-align-items: center;
   align-items: center;

    -webkit-box-pack: center; -moz-box-pack: center; 
   -ms-flex-pack: center; 
   -webkit-justify-content: center;
   justify-content: center;

   margin: 0;
   height: 100%;
   width: 100% /* needed for Firefox */
} 

h1 {
   display: -webkit-box; display: -moz-box;
   display: -ms-flexbox;
   display: -webkit-flex;
   display: flex;
 
   -webkit-box-align: center; -moz-box-align: center;
   -ms-flex-align: center;
   -webkit-align-items: center;
   align-items: center;

   height: 10rem;
}

I’ve included all of the different prefixed versions in the CSS above, from the very oldest, which is still needed, to the modern and hopefully final syntax. This might look confusing, but the different syntaxes map fairly well to each other, and I’ve included tables at the end of this article to show the exact mappings.

This is not exactly all of the CSS needed for our example, because I’ve stripped out the extra styling that you probably already know how to use in order to save space.

Let’s look at the CSS that is needed to center the heading on the page. First, we set the html and body elements to have 100% height and remove any margins. This will make the container of our h1 take up the full height of the browser’s window. Firefox also needs a width specified on the body to force it to behave. Now, we just need to center everything.

Enabling Flexbox

Because the body element contains the heading that we want to center, we will set its display value to flex:


body {
   display: flex;
}

This switches the body element to use the flexbox layout, rather than the regular block layout. All of its children in the flow of the document (i.e. not absolutely positioned elements) will now become flex items.

The syntax used by IE 10 is display: -ms-flexbox, while older Firefox and WebKit browsers use display: -prefix-box (where prefix is either moz or webkit). You can see the tables at the end of this article to see the mappings of the various versions.

What do we gain now that our elements have been to yoga class and become all flexible? They gain untold powers: they can flex their size and position relative to the available space; they can be laid out either horizontally or vertically; and they can even achieve source-order independence. (Two holy grails in one specification? We’re doing well.)

Centering Horizontally

Next, we want to horizontally center our h1 element. No big deal, you might say; but it is somewhat easier than playing around with auto margins. We just need to tell the flexbox to center its flex items. By default, flex items are laid out horizontally, so setting the justify-content property will align the items along the main axis:


body {
   display: flex;
   justify-content: center;
}

For IE 10, the property is called flex-pack, while for older browsers it is box-pack (again, with the appropriate prefixes). The other possible values are flex-start, flex-end, space-between and space-around. These are start, end, justify and distribute, respectively, in IE 10 and the old specification (distribute is, however, not supported in the old specification). The flex-start value aligns to the left (or to the right with right-to-left text), flex-end aligns to the right, space-between evenly distributes the elements along the axis, and space-around evenly distributes along the axis, with half-sized spaces at the start and end of the line.

To explicitly set the axis that the element is aligned along, you can do this with the flex-flow property. The default is row, which will give us the same result that we’ve just achieved. To align along the vertical axis, we can use flex-flow: column. If we add this to our example, you will notice that the element is vertically centered but loses the horizontal centering. Reversing the order by appending -reverse to the row or column values is also possible (flex-flow: row-reverse or flex-flow: column-reverse), but that won’t do much in our example because we have only one item.

There are some differences here in the various versions of the specification, which are highlighted at the end of this article. Another caveat to bear in mind is that flex-flow directions are writing-mode sensitive. That is, when using writing-mode: vertical-rl to switch to vertical text layout (as used traditionally in China, Japan and Korea), flex-flow: row will align the items vertically, and column will align them horizontally.

Centering Vertically

Centering vertically is as easy as centering horizontally. We just need to use the appropriate property to align along the “cross-axis.” The what? The cross-axis is basically the axis perpendicular to the main one. So, if flex items are aligned horizontally, then the cross-axis would be vertical, and vice versa. We set this with the align-items property (flex-align in IE 10, and box-align for older browsers):


body {
   /* Remember to use the other versions for IE 10 and older browsers! */
   display: flex;
   justify-content: center;
   align-items: center;
}

This is all there is to centering elements with flexbox! We can also use the flex-start (start) and flex-end (end) values, as well as baseline and stretch. Let’s have another look at the finished example:

figure1.1_mini
Simple horizontal and vertical centering using flexbox. Larger view.

You might notice that the text is also center-aligned vertically inside the h1 element. This could have been done with margins or a line height, but we used flexbox again to show that it works with anonymous boxes (in this case, the line of text inside the h1 element). No matter how high the h1 element gets, the text will always be in the center:


h1 {
   /* Remember to use the other versions for IE 10 and older browsers! */
   display: flex;
   align-items: center;
   height: 10rem;
}

Flexible Sizes

If centering elements was all flexbox could do, it’d be pretty darn cool. But there is more. Let’s see how flex items can expand and contract to fit the available space within a flexbox element. Point your browser to this next example.

figure1.2_mini
An interactive slideshow built using flexbox. Larger view.

The HTML and CSS for this example are similar to the previous one’s. We’re enabling flexbox and centering the elements on the page in the same way. In addition, we want to make the title (inside the header element) remain consistent in size, while the five boxes (the section elements) adjust in size to fill the width of the window. To do this, we use the new flex property:


section {
   /* removed other styles to save space */
   -prefix-box-flex: 1; /* old spec webkit, moz */
   flex: 1;
   height: 250px;
}

What we’ve just done here is to make each section element take up 1 flex unit. Because we haven’t set any explicit width, each of the five boxes will be the same width. The header element will take up a set width (277 pixels) because it is not flexible. We divide the remaining width inside the body element by 5 to calculate the width of each of the section elements. Now, if we resize the browser window, the section elements will grow or shrink.

In this example, we’ve set a consistent height, but this could be set to be flexible, too, in exactly the same way. We probably wouldn’t always want all elements to be the same size, so let’s make one bigger. On hover, we’ve set the element to take up 2 flex units:


section:hover {
   -prefix-box-flex: 2;
   flex: 2;
   cursor: pointer;
}

Now the available space is divided by 6 rather than 5, and the hovered element gets twice the base amount. Note that an element with 2 flex units does not necessarily become twice as wide as one with 1 unit. It just gets twice the share of the available space added to its “preferred width.” In our examples, the “preferred width” is 0 (the default).

Source-Order Independence

For our last party trick, we’ll study how to achieve source-order independence in our layouts. When clicking on a box, we will tell that element to move to the left of all the other boxes, directly after the title. All we have to do is set the order with the order property. By default, all flex items are in the 0 position. Because they’re in the same position, they follow the source order. Click on your favorite person in the updated example to see their order change.

figure1.3_mini
An interactive slideshow with flex-order. Larger view.

To make our chosen element move to the first position, we just have to set a lower number. I chose -1. We also need to set the header to -1 so that the selected section element doesn’t get moved before it:


header {
   -prefix-box-ordinal-group: 1; /* old spec; must be positive */
   -ms-flex-order: -1; /* IE 10 syntax */
   order: -1; /* new syntax */
} 

section[aria-pressed="true"] {
   /* Set order lower than 0 so it moves before other section elements,
      except old spec, where it must be positive.
 */
   -prefix-box-ordinal-group: 1;
   -ms-flex-order: -1;
   order: -1;

   -prefix-box-flex: 3;
   flex: 3;
   max-width: 370px; /* Stops it from getting too wide. */
}

In the old specification, the property for setting the order (box-ordinal-group) accepts only a positive integer. Therefore, I’ve set the order to 2 for each section element (code not shown) and updated it to 1 for the active element. If you are wondering what aria-pressed="true" means in the example above, it is a WAI-ARIA attribute/value that I add via JavaScript when the user clicks on one of the sections.

This relays accessibility hints to the underlying system and to assistive technology to tell the user that that element is pressed and, thus, active. If you’d like more information on WAI-ARIA, check out “Introduction to WAI-ARIA” by Gez Lemon. Because I’m adding the attribute after the user clicks, this example requires a simple JavaScript file in order to work, but flexbox itself doesn’t require it; it’s just there to handle the user interaction.

Hopefully, this has given you some inspiration and enough introductory knowledge of flexbox to enable you to experiment with your own designs.

Syntax Changes

As you will have noticed throughout this article, the syntax has changed a number of times since it was first implemented. To aid backward- and forward-porting between the different versions, we’ve included tables below, which map the changes between the specifications.

Specification versions

Specification
IE
Opera
Firefox
Chrome
Safari

Standard
11?
12.10+ *
Behind flag
21+ (-webkit-)

Mid
10 (-ms-)

Old

3+ (-moz-)
<21 (-webkit-)
3+ (-webkit-)

* Opera will soon switch to WebKit. It will then require the -webkit- prefix if it has not been dropped by that time.

Enabling flexbox: setting an element to be a flex container

Specification
Property name
Block-level flex
Inline-level flex

Standard
display
flex
inline-flex

Mid
display
flexbox
inline-flexbox

Old
display
box
inline-box

Axis alignment: specifying alignment of items along the main flexbox axis

Specification
Property name
start
center
end
justify
distribute

Standard
justify-content
flex-start
center
flex-end
space-between
space-around

Mid
flex-pack
start
center
end
justify
distribute

Old
box-pack
start
center
end
justify
N/A

Cross-axis alignment: specifying alignment of items along the cross-axis

Specification
Property name
start
center
end
baseline
stretch

Standard
align-items
flex-start
center
flex-end
baseline
stretch

Mid
flex-align
start
center
end
baseline
stretch

Old
box-align
start
center
end
baseline
stretch

Individual cross-axis alignment: override to align individual items along the cross-axis

Specification
Property name
auto
start
center
end
baseline
stretch

Standard
align-self
auto
flex-start
center
flex-end
baseline
stretch

Mid
flex-item-align
auto
start
center
end
baseline
stretch

Old
N/A

Flex line alignment: specifying alignment of flex lines along the cross-axis

Specification
Property name
start
center
end
justify
distribute
stretch

Standard
align-content
flex-start
center
flex-end
space-between
space-around
stretch

Mid
flex-line-pack
start
center
end
justify
distribute
stretch

Old
N/A

This takes effect only when there are multiple flex lines, which is the case when flex items are allowed to wrap using the flex-wrap property and there isn’t enough space for all flex items to display on one line. This will align each line, rather than each item.

Display order: specifying the order of flex items

Specification
Property name
Value

Standard
order

Mid
flex-order
<number>

Old
box-ordinal-group
<integer>

Flexibility: specifying how the size of items flex

Specification
Property name
Value

Standard
flex
none | [ <flex-grow> <flex-shrink>? || <flex-basis>]

Mid
flex
none | [ [ <pos-flex> <neg-flex>? ] || <preferred-size> ]

Old
box-flex
<number>

The flex property is more or less unchanged between the new standard and the draft supported by Microsoft. The main difference is that it has been converted to a shorthand in the new version, with separate properties: flex-grow, flex-shrink and flex-basis. The values may be used in the same way in the shorthand. However, the default value for flex-shrink (previously called negative flex) is now 1. This means that items do not shrink by default. Previously, negative free space would be distributed using the flex-shrink ratio, but now it is distributed in proportion to flex-basis multiplied by the flex-shrink ratio.

Direction: specifying the direction of the main flexbox axis

Specification
Property name
Horizontal
Reversed horizontal
Vertical
Reversed vertical

Standard
flex-direction
row
row-reverse
column
column-reverse

Mid
flex-direction
row
row-reverse
column
column-reverse

Old
box-orient

box-direction
horizontal

normal
horizontal

reverse
vertical

normal
vertical

reverse

In the old version of the specification, the box-direction property needs to be set to reverse to get the same behavior as row-reverse or column-reverse in the later version of the specification. This can be omitted if you want the same behavior as row or column because normal is the initial value.

When setting the direction to reverse, the main flexbox axis is flipped. This means that when using a left-to-right writing system, the items will display from right to left when row-reverse is specified. Similarly, column-reverse will lay out flex items from bottom to top, instead of top to bottom.

The old version of the specification also has writing mode-independent values for box-orient. When using a left-to-write writing system, horizontal may be substituted for inline-axis, and vertical may be substituted for block-axis. If you are using a top-to-bottom writing system, such as those traditional in East Asia, then these values would be flipped.

Wrapping: specifying whether and how flex items wrap along the cross-axis

Specification
Property name
No wrapping
Wrapping
Reversed wrap

Standard
flex-wrap
nowrap
wrap
wrap-reverse

Mid
flex-wrap
nowrap
wrap
wrap-reverse

Old
box-lines
single
multiple
N/A

The wrap-reverse value flips the start and end of the cross-axis, so that if flex items are laid out horizontally, instead of items wrapping onto a new line below, they will wrap onto a new line above.

At the time of writing, Firefox does not support the flex-wrap or older box-lines property. It also doesn’t support the shorthand.

The current specification has a flex-flow shorthand, which controls both wrapping and direction. The behavior is the same as the one in the version of the specification implemented by IE 10. It is also currently not supported by Firefox, so I would recommend to avoid using it when specifying only the flex-direction value.

Conclusion

Well, that’s a (flex-)wrap. In this article, I’ve introduced some of the myriad of possibilities afforded by flexbox. Be it source-order independence, flexible sizing or just the humble centering of elements, I’m sure you can find ways to employ flexbox in your websites and applications. The syntax has settled down (finally!), and implementations are here. All major browsers now support flexbox in at least their latest versions.

While some browsers use an older syntax, Firefox looks like it is close to updating, and IE 11 uses the latest version in leaked Windows Blue builds. There is currently no word on Safari, but it is a no-brainer considering that Chrome had the latest syntax before the Blink-WebKit split. For the time being, use the tables above to map the various syntaxes, and get your flex on.

Layout in CSS is only getting more powerful, and flexbox is one of the first steps out of the quagmire we’ve found ourselves in over the years, first with table-based layouts, then float-based layouts. IE 10 already supports an early draft of the Grid layout specification, which is great for page layout, and Regions and Exclusions will revolutionize how we handle content flow and layout.

Flexbox can be used today if you only need to support relatively modern browsers or can provide a fallback, and in the not too distant future, all sorts of options will be available, so that we can use the best tool for the job. Flexbox is shaping up to be a mighty fine tool.

Further Reading

(al)

© David Storey for Smashing Magazine, 2013.

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We’ve all been there: that bit of JavaScript functionality that started out as just a handful of lines grows to a dozen, then two dozen, then more. Along the way, a function picks up a few more arguments; a conditional picks up a few more conditions. And then one day, the bug report comes in: something’s broken, and it’s up to us to untangle the mess.

As we ask our client-side code to take on more and more responsibilities—indeed, whole applications are living largely in the browser these days—two things are becoming clear. One, we can’t just point and click our way through testing that things are working as we expect; automated tests are key to having confidence in our code. Two, we’re probably going to have to change how we write our code in order to make it possible to write tests.

Really, we need to change how we code? Yes—because even if we know that automated tests are a good thing, most of us are probably only able to write integration tests right now. Integration tests are valuable because they focus on how the pieces of an application work together, but what they don’t do is tell us whether individual units of functionality are behaving as expected.

That’s where unit testing comes in. And we’ll have a very hard time writing unit tests until we start writing testable JavaScript.

Unit vs. integration: what’s the difference?

Writing integration tests is usually fairly straightforward: we simply write code that describes how a user interacts with our app, and what the user should expect to see as she does. Selenium is a popular tool for automating browsers. Capybara for Ruby makes it easy to talk to Selenium, and there are plenty of tools for other languages, too.

Here’s an integration test for a portion of a search app:

def test_search
  fill_in('q', :with => 'cat')
  find('.btn').click
  assert( find('#results li').has_content?('cat'), 'Search results are shown' )
  assert( page.has_no_selector?('#results li.no-results'), 'No results is not shown' )
end

Whereas an integration test is interested in a user’s interaction with an app, a unit test is narrowly focused on a small piece of code:

When I call a function with a certain input, do I receive the expected output?

Apps that are written in a traditional procedural style can be very difficult to unit test—and difficult to maintain, debug, and extend, too. But if we write our code with our future unit testing needs in mind, we will not only find that writing the tests becomes more straightforward than we might have expected, but also that we’ll simply write better code, too.

To see what I’m talking about, let’s take a look at a simple search app:

Srchr

When a user enters a search term, the app sends an XHR to the server for the corresponding data. When the server responds with the data, formatted as JSON, the app takes that data and displays it on the page, using client-side templating. A user can click on a search result to indicate that he “likes” it; when this happens, the name of the person he liked is added to the “Liked” list on the right-hand side.

A “traditional” JavaScript implementation of this app might look like this:

var tmplCache = {};

function loadTemplate (name) {
  if (!tmplCache[name]) {
    tmplCache[name] = $.get('/templates/' + name);
  }
  return tmplCache[name];
}

$(function () {

  var resultsList = $('#results');
  var liked = $('#liked');
  var pending = false;

  $('#searchForm').on('submit', function (e) {
    e.preventDefault();

    if (pending) { return; }

    var form = $(this);
    var query = $.trim( form.find('input[name="q"]').val() );

    if (!query) { return; }

    pending = true;

    $.ajax('/data/search.json', {
      data : { q: query },
      dataType : 'json',
      success : function (data) {
        loadTemplate('people-detailed.tmpl').then(function (t) {
          var tmpl = _.template(t);
          resultsList.html( tmpl({ people : data.results }) );
          pending = false;
        });
      }
    });

    $('<li>', {
      'class' : 'pending',
      html : 'Searching &hellip;'
    }).appendTo( resultsList.empty() );
  });

  resultsList.on('click', '.like', function (e) {
    e.preventDefault();
    var name = $(this).closest('li').find('h2').text();
    liked.find('.no-results').remove();
    $('<li>', { text: name }).appendTo(liked);
  });

});

My friend Adam Sontag calls this Choose Your Own Adventure code—on any given line, we might be dealing with presentation, or data, or user interaction, or application state. Who knows! It’s easy enough to write integration tests for this kind of code, but it’s hard to test individual units of functionality.

What makes it hard? Four things:

  • A general lack of structure; almost everything happens in a $(document).ready() callback, and then in anonymous functions that can’t be tested because they aren’t exposed.
  • Complex functions; if a function is more than 10 lines, like the submit handler, it’s highly likely that it’s doing too much.
  • Hidden or shared state; for example, since pending is in a closure, there’s no way to test whether the pending state is set correctly.
  • Tight coupling; for example, a $.ajax success handler shouldn’t need direct access to the DOM.

Organizing our code

The first step toward solving this is to take a less tangled approach to our code, breaking it up into a few different areas of responsibility:

  • Presentation and interaction
  • Data management and persistence
  • Overall application state
  • Setup and glue code to make the pieces work together

In the “traditional” implementation shown above, these four categories are intermingled—on one line we’re dealing with presentation, and two lines later we might be communicating with the server.

Code Lines

While we can absolutely write integration tests for this code—and we should!—writing unit tests for it is pretty difficult. In our functional tests, we can make assertions such as “when a user searches for something, she should see the appropriate results,” but we can’t get much more specific. If something goes wrong, we’ll have to track down exactly where it went wrong, and our functional tests won’t help much with that.

If we rethink how we write our code, though, we can write unit tests that will give us better insight into where things went wrong, and also help us end up with code that’s easier to reuse, maintain, and extend.

Our new code will follow a few guiding principles:

  • Represent each distinct piece of behavior as a separate object that falls into one of the four areas of responsibility and doesn’t need to know about other objects. This will help us avoid creating tangled code.
  • Support configurability, rather than hard-coding things. This will prevent us from replicating our entire HTML environment in order to write our tests.
  • Keep our objects’ methods simple and brief. This will help us keep our tests simple and our code easy to read.
  • Use constructor functions to create instances of objects. This will make it possible to create “clean” copies of each piece of code for the sake of testing.

To start with, we need to figure out how we’ll break our application into different pieces. We’ll have three pieces dedicated to presentation and interaction: the Search Form, the Search Results, and the Likes Box.

Application Views

We’ll also have a piece dedicated to fetching data from the server and a piece dedicated to gluing everything together.

Let’s start by looking at one of the simplest pieces of our application: the Likes Box. In the original version of the app, this code was responsible for updating the Likes Box:

var liked = $('#liked');

var resultsList = $('#results');


// ...


resultsList.on('click', '.like', function (e) {
  e.preventDefault();

  var name = $(this).closest('li').find('h2').text();

  liked.find( '.no-results' ).remove();

  $('<li>', { text: name }).appendTo(liked);

});

The Search Results piece is completely intertwined with the Likes Box piece and needs to know a lot about its markup. A much better and more testable approach would be to create a Likes Box object that’s responsible for manipulating the DOM related to the Likes Box:

var Likes = function (el) {
  this.el = $(el);
  return this;
};

Likes.prototype.add = function (name) {
  this.el.find('.no-results').remove();
  $('<li>', { text: name }).appendTo(this.el);
};

This code provides a constructor function that creates a new instance of a Likes Box. The instance that’s created has an .add() method, which we can use to add new results. We can write a couple of tests to prove that it works:

var ul;

setup(function(){
  ul = $('<ul><li class="no-results"></li></ul>');
});

test('constructor', function () {
  var l = new Likes(ul);
  assert(l);
});

test('adding a name', function () {
  var l = new Likes(ul);
  l.add('Brendan Eich');

  assert.equal(ul.find('li').length, 1);
  assert.equal(ul.find('li').first().html(), 'Brendan Eich');
  assert.equal(ul.find('li.no-results').length, 0);
});

Not so hard, is it? Here we’re using Mocha as the test framework, and Chai as the assertion library. Mocha provides the test and setup functions; Chai provides assert. There are plenty of other test frameworks and assertion libraries to choose from, but for the sake of an introduction, I find these two work well. You should find the one that works best for you and your project—aside from Mocha, QUnit is popular, and Intern is a new framework that shows a lot of promise.

Our test code starts out by creating an element that we’ll use as the container for our Likes Box. Then, it runs two tests: one is a sanity check to make sure we can make a Likes Box; the other is a test to ensure that our .add() method has the desired effect. With these tests in place, we can safely refactor the code for our Likes Box, and be confident that we’ll know if we break anything.

Our new application code can now look like this:

var liked = new Likes('#liked');
var resultsList = $('#results');



// ...



resultsList.on('click', '.like', function (e) {
  e.preventDefault();

  var name = $(this).closest('li').find('h2').text();

  liked.add(name);
});

The Search Results piece is more complex than the Likes Box, but let’s take a stab at refactoring that, too. Just as we created an .add() method on the Likes Box, we also want to create methods for interacting with the Search Results. We’ll want a way to add new results, as well as a way to “broadcast” to the rest of the app when things happen within the Search Results—for example, when someone likes a result.

var SearchResults = function (el) {
  this.el = $(el);
  this.el.on( 'click', '.btn.like', _.bind(this._handleClick, this) );
};

SearchResults.prototype.setResults = function (results) {
  var templateRequest = $.get('people-detailed.tmpl');
  templateRequest.then( _.bind(this._populate, this, results) );
};

SearchResults.prototype._handleClick = function (evt) {
  var name = $(evt.target).closest('li.result').attr('data-name');
  $(document).trigger('like', [ name ]);
};

SearchResults.prototype._populate = function (results, tmpl) {
  var html = _.template(tmpl, { people: results });
  this.el.html(html);
};

Now, our old app code for managing the interaction between Search Results and the Likes Box could look like this:

var liked = new Likes('#liked');
var resultsList = new SearchResults('#results');


// ...


$(document).on('like', function (evt, name) {
  liked.add(name);
})

It’s much simpler and less entangled, because we’re using the document as a global message bus, and passing messages through it so individual components don’t need to know about each other. (Note that in a real app, we’d use something like Backbone or the RSVP library to manage events. We’re just triggering on document to keep things simple here.) We’re also hiding all the dirty work—such as finding the name of the person who was liked—inside the Search Results object, rather than having it muddy up our application code. The best part: we can now write tests to prove that our Search Results object works as we expect:

var ul;
var data = [ /* fake data here */ ];

setup(function () {
  ul = $('<ul><li class="no-results"></li></ul>');
});

test('constructor', function () {
  var sr = new SearchResults(ul);
  assert(sr);
});

test('display received results', function () {
  var sr = new SearchResults(ul);
  sr.setResults(data);

  assert.equal(ul.find('.no-results').length, 0);
  assert.equal(ul.find('li.result').length, data.length);
  assert.equal(
    ul.find('li.result').first().attr('data-name'),
    data[0].name
  );
});

test('announce likes', function() {
  var sr = new SearchResults(ul);
  var flag;
  var spy = function () {
    flag = [].slice.call(arguments);
  };

  sr.setResults(data);
  $(document).on('like', spy);

  ul.find('li').first().find('.like.btn').click();

  assert(flag, 'event handler called');
  assert.equal(flag[1], data[0].name, 'event handler receives data' );
});

The interaction with the server is another interesting piece to consider. The original code included a direct $.ajax() request, and the callback interacted directly with the DOM:

$.ajax('/data/search.json', {
  data : { q: query },
  dataType : 'json',
  success : function( data ) {
    loadTemplate('people-detailed.tmpl').then(function(t) {
      var tmpl = _.template( t );
      resultsList.html( tmpl({ people : data.results }) );
      pending = false;
    });
  }
});

Again, this is difficult to write a unit test for, because so many different things are happening in just a few lines of code. We can restructure the data portion of our application as an object of its own:

var SearchData = function () { };

SearchData.prototype.fetch = function (query) {
  var dfd;

  if (!query) {
    dfd = $.Deferred();
    dfd.resolve([]);
    return dfd.promise();
  }

  return $.ajax( '/data/search.json', {
    data : { q: query },
    dataType : 'json'
  }).pipe(function( resp ) {
    return resp.results;
  });
};

Now, we can change our code for getting the results onto the page:

var resultsList = new SearchResults('#results');

var searchData = new SearchData();

// ...

searchData.fetch(query).then(resultsList.setResults);

Again, we’ve dramatically simplified our application code, and isolated the complexity within the Search Data object, rather than having it live in our main application code. We’ve also made our search interface testable, though there are a couple caveats to bear in mind when testing code that interacts with the server.

The first is that we don’t want to actually interact with the server—to do so would be to reenter the world of integration tests, and because we’re responsible developers, we already have tests that ensure the server does the right thing, right? Instead, we want to “mock” the interaction with the server, which we can do using the Sinon library. The second caveat is that we should also test non-ideal paths, such as an empty query.

test('constructor', function () {
  var sd = new SearchData();
  assert(sd);
});

suite('fetch', function () {
  var xhr, requests;

  setup(function () {
    requests = [];
    xhr = sinon.useFakeXMLHttpRequest();
    xhr.onCreate = function (req) {
      requests.push(req);
    };
  });

  teardown(function () {
    xhr.restore();
  });

  test('fetches from correct URL', function () {
    var sd = new SearchData();
    sd.fetch('cat');

    assert.equal(requests[0].url, '/data/search.json?q=cat');
  });

  test('returns a promise', function () {
    var sd = new SearchData();
    var req = sd.fetch('cat');

    assert.isFunction(req.then);
  });

  test('no request if no query', function () {
    var sd = new SearchData();
    var req = sd.fetch();
    assert.equal(requests.length, 0);
  });

  test('return a promise even if no query', function () {
    var sd = new SearchData();
    var req = sd.fetch();

    assert.isFunction( req.then );
  });

  test('no query promise resolves with empty array', function () {
    var sd = new SearchData();
    var req = sd.fetch();
    var spy = sinon.spy();

    req.then(spy);

    assert.deepEqual(spy.args[0][0], []);
  });

  test('returns contents of results property of the response', function () {
    var sd = new SearchData();
    var req = sd.fetch('cat');
    var spy = sinon.spy();

    requests[0].respond(
      200, { 'Content-type': 'text/json' },
      JSON.stringify({ results: [ 1, 2, 3 ] })
    );

    req.then(spy);

    assert.deepEqual(spy.args[0][0], [ 1, 2, 3 ]);
  });
});

For the sake of brevity, I’ve left out the refactoring of the Search Form, and also simplified some of the other refactorings and tests, but you can see a finished version of the app here if you’re interested.

When we’re done rewriting our application using testable JavaScript patterns, we end up with something much cleaner than what we started with:

$(function() {
  var pending = false;

  var searchForm = new SearchForm('#searchForm');
  var searchResults = new SearchResults('#results');
  var likes = new Likes('#liked');
  var searchData = new SearchData();

  $(document).on('search', function (event, query) {
    if (pending) { return; }

    pending = true;

    searchData.fetch(query).then(function (results) {
      searchResults.setResults(results);
      pending = false;
    });

    searchResults.pending();
  });

  $(document).on('like', function (evt, name) {
    likes.add(name);
  });
});

Even more important than our much cleaner application code, though, is the fact that we end up with a codebase that is thoroughly tested. That means we can safely refactor it and add to it without the fear of breaking things. We can even write new tests as we find new issues, and then write the code that makes those tests pass.

Testing makes life easier in the long run

It’s easy to look at all of this and say, “Wait, you want me to write more code to do the same job?”

The thing is, there are a few inescapable facts of life about Making Things On The Internet. You will spend time designing an approach to a problem. You will test your solution, whether by clicking around in a browser, writing automated tests, or—shudder—letting your users do your testing for you in production. You will make changes to your code, and other people will use your code. Finally: there will be bugs, no matter how many tests you write.

The thing about testing is that while it might require a bit more time at the outset, it really does save time in the long run. You’ll be patting yourself on the back the first time a test you wrote catches a bug before it finds its way into production. You’ll be grateful, too, when you have a system in place that can prove that your bug fix really does fix a bug that slips through.

Additional resources

This article just scratches the surface of JavaScript testing, but if you’d like to learn more, check out:

  • My presentation from the 2012 Full Frontal conference in Brighton, UK.
  • Grunt, a tool that helps automate the testing process and lots of other things.
  • Test-Driven JavaScript Development by Christian Johansen, the creator of the Sinon library. It is a dense but informative examination of the practice of testing JavaScript.
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Great design is a product of care and attention applied to areas that matter, resulting in a useful, understandable, and hopefully beautiful user interface. But don’t be fooled into thinking that design is left only for designers.

There is a lot of design in code, and I don’t mean code that builds the user interface—I mean the design of code.

Well-designed code is much easier to maintain, optimize, and extend, making for more efficient developers. That means more focus and energy can be spent on building great things, which makes everyone happy—users, developers, and stakeholders.

There are three high-level, language-agnostic aspects to code design that are particularly important.

  1. System architecture—The basic layout of the codebase. Rules that govern how various components, such as models, views, and controllers, interact with each other.
  2. Maintainability—How well can the code be improved and extended?
  3. Reusability—How reusable are the application’s components? How easily can each implementation of a component be customized?

In looser languages, specifically JavaScript, it takes a bit of discipline to write well-designed code. The JavaScript environment is so forgiving that it’s easy to throw bits and pieces everywhere and still have things work. Establishing system architecture early (and sticking to it!) provides constraints to your codebase, ensuring consistency throughout.

One approach I’m fond of consists of a tried-and-true software design pattern, the module pattern, whose extensible structure lends itself to a solid system architecture and a maintainable codebase. I like building modules within a jQuery plugin, which makes for beautiful reusability, provides robust options, and exposes a well-crafted API.

Below, I’ll walk through how to craft your code into well-organized components that can be reused in projects to come.

The module pattern

There are a lot of design patterns out there, and equally as many resources on them. Addy Osmani wrote an amazing (free!) book on design patterns in JavaScript, which I highly recommend to developers of all levels.

The module pattern is a simple structural foundation that can help keep your code clean and organized. A “module” is just a standard object literal containing methods and properties, and that simplicity is the best thing about this pattern: even someone unfamiliar with traditional software design patterns would be able to look at the code and instantly understand how it works.

In applications that use this pattern, each component gets its own distinct module. For example, to build autocomplete functionality, you’d create a module for the textfield and a module for the results list. These two modules would work together, but the textfield code wouldn’t touch the results list code, and vice versa.

That decoupling of components is why the module pattern is great for building solid system architecture. Relationships within the application are well-defined; anything related to the textfield is managed by the textfield module, not strewn throughout the codebase—resulting in clear code.

Another benefit of module-based organization is that it is inherently maintainable. Modules can be improved and optimized independently without affecting any other part of the application.

I used the module pattern for the basic structure of jPanelMenu, the jQuery plugin I built for off-canvas menu systems. I’ll use that as an example to illustrate the process of building a module.

Building a module

To begin, I define three methods and a property that are used to manage the interactions of the menu system.

var jpm = {
    animated: true,
    openMenu: function( ) {
        …
        this.setMenuStyle( );
    },
    closeMenu: function( ) {
        …
        this.setMenuStyle( );
    },
    setMenuStyle: function( ) { … }
};

The idea is to break down code into the smallest, most reusable bits possible. I could have written just one toggleMenu( ) method, but creating distinct openMenu( ) and closeMenu( ) methods provides more control and reusability within the module.

Notice that calls to module methods and properties from within the module itself (such as the calls to setMenuStyle( )) are prefixed with the this keyword—that’s how modules access their own members.

That’s the basic structure of a module. You can continue to add methods and properties as needed, but it doesn’t get any more complex than that. After the structural foundations are in place, the reusability layer—options and an exposed API—can be built on top.

jQuery plugins

The third aspect of well-designed code is probably the most crucial: reusability. This section comes with a caveat. While there are obviously ways to build and implement reusable components in raw JavaScript (we’re about 90 percent of the way there with our module above), I prefer to build jQuery plugins for more complex things, for a few reasons.

Most importantly, it’s a form of unobtrusive communication. If you used jQuery to build a component, you should make that obvious to those implementing it. Building the component as a jQuery plugin is a great way to say that jQuery is required.

In addition, the implementation code will be consistent with the rest of the jQuery-based project code. That’s good for aesthetic reasons, but it also means (to an extent) that developers can predict how to interact with the plugin without too much research. Just one more way to build a better developer interface.

Before you begin building a jQuery plugin, ensure that the plugin does not conflict with other JavaScript libraries using the $ notation. That’s a lot simpler than it sounds—just wrap your plugin code like so:

(function($) {
    // jQuery plugin code here
})(jQuery);

Next, we set up our plugin and drop our previously built module code inside. A plugin is just a method defined on the jQuery ($) object.

(function($) {
    $.jPanelMenu = function( ) {
        var jpm = {
            animated: true,
            openMenu: function( ) {
                …
                this.setMenuStyle( );
            },
            closeMenu: function( ) {
                …
                this.setMenuStyle( );
            },
            setMenuStyle: function( ) { … }
        };
    };
})(jQuery);

All it takes to use the plugin is a call to the function you just created.

var jpm = $.jPanelMenu( );

Options

Options are essential to any truly reusable plugin because they allow for customizations to each implementation. Every project brings with it a slew of design styles, interaction types, and content structures. Customizable options help ensure that you can adapt the plugin to fit within those project constraints.

It’s best practice to provide good default values for your options. The easiest way to do that is to use jQuery’s $.extend( ) method, which accepts (at least) two arguments.

As the first argument of $.extend( ), define an object with all available options and their default values. As the second argument, pass through the passed-in options. This will merge the two objects, overriding the defaults with any passed-in options.

(function($) {
    $.jPanelMenu = function(options) {
        var jpm = {
            options: $.extend({
                'animated': true,
                'duration': 500,
                'direction': 'left'
            }, options),
            openMenu: function( ) {
                …
                this.setMenuStyle( );
            },
            closeMenu: function( ) {
                …
                this.setMenuStyle( );
            },
            setMenuStyle: function( ) { … }
        };
    };
})(jQuery);

Beyond providing good defaults, options become almost self-documenting—someone can look at the code and see all of the available options immediately.

Expose as many options as is feasible. The customization will help in future implementations, and flexibility never hurts.

API

Options are terrific ways to customize how a plugin works. An API, on the other hand, enables extensions to the plugin’s functionality by exposing methods and properties for the implementation code to take advantage of.

While it’s great to expose as much as possible through an API, the outside world shouldn’t have access to all internal methods and properties. Ideally, you should expose only the elements that will be used.

In our example, the exposed API should include calls to open and close the menu, but nothing else. The internal setMenuStyle( ) method runs when the menu opens and closes, but the public doesn’t need access to it.

To expose an API, return an object with any desired methods and properties at the end of the plugin code. You can even map returned methods and properties to those within the module code—this is where the beautiful organization of the module pattern really shines.

(function($) {
    $.jPanelMenu = function(options) {
        var jpm = {
            options: $.extend({
                'animated': true,
                'duration': 500,
                'direction': 'left'
            }, options),
            openMenu: function( ) {
                …
                this.setMenuStyle( );
            },
            closeMenu: function( ) {
                …
                this.setMenuStyle( );
            },
            setMenuStyle: function( ) { … }
        };

        return {
            open: jpm.openMenu,
            close: jpm.closeMenu,
            someComplexMethod: function( ) { … }
        };
    };
})(jQuery);

API methods and properties will be available through the object returned from the plugin initialization.

var jpm = $.jPanelMenu({
    duration: 1000,
    …
});
jpm.open( );

Polishing developer interfaces

With just a few simple constructs and guidelines, we’ve built ourselves a reusable, extensible plugin that will help make our lives easier. Like any part of what we do, experiment with this structure to see if it works for you, your team, and your workflow.

Whenever I find myself building something with a potential for reuse, I break it out into a module-based jQuery plugin. The best part about this approach is that it forces you to use—and test—the code you write. By using something as you build it, you’ll quickly identify strengths, discover shortcomings, and plan changes.

This process leads to battle-tested code ready for open-source contributions, or to be sold and distributed. I’ve released my (mostly) polished plugins as open-source projects on GitHub.

Even if you aren’t building something to be released in the wild, it’s still important to think about the design of your code. Your future self will thank you.

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I know you’ve been asked this plenty of times already, but: no new vendor prefixes, right? Right?

Nope, none! They’re great in theory but turns out they fail in practice, so we’re joining Mozilla and the W3C CSS WG and moving away them. There’s a few parts to this.

Firstly, we won’t be migrating the existing -webkit- prefixed properties to a -chrome- or -blink- prefix, that’d just make extra work for everyone. Secondly, we inherited some existing properties that are prefixed. Some, like -webkit-transform, are standards track and we work with the CSS WG to move ahead those standards while we fix any remaining issues in our implementation and we’ll unprefix them when they’re ready. Others, like -webkit-box-reflect are not standards track and we’ll bring them to standards bodies or responsibly deprecate these on a case-by-case basis. Lastly, we’re not introducing any new CSS properties behind a prefix.

Pinky swear?

Totes. New stuff will be available to experiment with behind a flag you can turn on in about:flags called “Experimental Web Platform Features”. When the feature is ready, it’ll graduate to Canary, and then follow its ~12 week path down through Dev Channel, Beta to all users at Stable.

The Blink prefix policy is documented and, in fact, WebKit just nailed down their prefix policy going forward. If you’re really into prefix drama (and who isn’t!) Chris Wilson and I discussed this a lot more on the Web Ahead podcast [37:20].

How long before we can try Blink out in Chrome?

Blink’s been in Chrome Canary as of the day we announced it. The codebase was 99.9% the same when Blink launched, so no need to rush out and check everything. All your sites should be pretty much the same.

Chrome 27 has the Blink engine, and that’s available on the beta channel for
Win, Mac, Linux, ChromeOS and Android. (See the full beta/stable/dev/canary
view
).

While the internals are apt to be fairly different, will there be any radical changes to the rendering side of things in the near future?

Nothing too alarming, layout and CSS stuff is all staying the same. Grid layout is still in development, though, and our Windows text rendering has been getting a new backend that we can hook up soon, greatly boosting the quality of webfont rendering there.

We’re also interested in better taking advantage of multiple cores on machines, so the more we can move painting, layout (aka reflow), and style recalculation to a separate thread, but the faster everyone’s sites will render. We’re already doing multi-threaded painting on ChromeOS and Android, and looking into doing it on Mac & Windows. If you’re interested in these experimental efforts or watching new feature proposals, take a look at the blink-dev mailing list. A recent proposed experiment is called Oilpan, where we’ll look into the advantages of moving the implementation of Chrome’s DOM into JavaScript.

Will features added to Blink be contributed back to the WebKit project? Short term; long term?

Since Blink launched there’s been a few patches that have been landed in both Blink and WebKit, though this is expected to decline in the long-term, as the code bases will diverge.

When are we likely to start seeing Blink-powered versions of Chrome on Android? Is it even possible on iOS, or is iOS Chrome still stuck with a Safari webview due to Apple’s policies?

Blink is now in the Chrome Beta for Android. Chrome for iOS, due to platform limitations, is based on the WebKit-based WebView that’s provided by iOS.

Part of this move seems to be giving Google the freedom to remove old or disused features that have been collecting dust in WebKit for ages. There must be a few things high on that list—what are some of those things, and how can we be certain their removal won’t lead to the occasional broken website?

A few old ’n crusty things that we’re looking at removing: the isindex attribute, RangeException, and XMLHttpRequestException. Old things that have little use in the wild and just haven’t gotten a spring cleaning from the web platform for ages.

Now, we don’t want to break the web, and that’s something that web browser engineers have always been kept very aware of. We carefully gauge real-world usage of things like CSS and DOM features before deprecating anything. At Google we have a copy of the web that we run queries against, so we have a pretty OK idea of what CSS and JavaScript out there is using.

Blink also has over 32,000 tests in its test suite, and manual confirmation that over 100 sites work great before every release ships. And we’re working closely with the W3C and Adobe to share tests and testing infrastructure across browsers, with the goals of reducing maintenance burden, improving interoperability, and increasing test coverage. Eventually we’d like all new features to ship with shared conformance tests, ensuring interoperability even as we add cutting-edge stuff.

Still, any deprecation has to be done responsibly. There’s now a draft Blink process for deprecating features which includes:

  • Anonymous metrics to understand how much any specific feature is used “in the wild”
  • ”Intent to deprecate” emails that hit blink-dev months before anything is
    removed
  • Warnings that you’ll find in your DevTools console if you’re using anything
    deprecated
  • Mentions on the Chromium blog like this Chrome 27
    wrap-up
    .

Did part of the decision to branch away from WebKit involve resistance to adding a Dart VM? WebKit’s goals explicitly mention JavaScript, and Apple representatives have been fairly vocal about not seeing a need.

Nope, not at all. The decision was made by the core web platform engineers. Introducing a new VM to a browser introduces considerable maintenance cost (we saw this with V8 and JavaScriptCore both in WebKit) and right now Dart isn’t yet ready to be considered for an integration with Blink. (more on that in a sec). Blink’s got strong principles around compatibility risk and this guides a lot of the decisions around our commitments to potential features as they are proposed. You can hear a more complete answer here from Darin Fisher, one of the Chrome web platform leads.

Have any non-WebKit browsers recently expressed an interest in Dart? A
scripting language that only stands to work in one browser sounds a little
VBScript-y.

Not yet, but since Dart compiles to JavaScript and runs across the modern web, it’s not gated by other browsers integrating the VM. But it’s still early days, Dart has not yet reached a stable 1.0 milestone and that there are still technical challenges with the Dart VM around performance and memory management. Still, It’s important to point out that Dart is an open source project, with a bunch of external contributors and committers.

Let me take a moment to provide my own perspective on Dart. :) Now, as you know, I’m a JavaScript guy, so early on, I took a side and and considered Dart an enemy. JavaScript should win; Dart is bad! But then I came to realize the Dart guys aren’t just setting out to improve the authoring and scalability of web application development. They also really want the web to win.  Now I’ve recently spoke about how The Mobile Web Is In Trouble, and clarified that my priorities are seeing it provide a fantastic user experience to everyone. For me, seeing the mobile web be successful trumps language wars and certainly quibbling over syntax. So I’m happy to see developers embrace the authoring advantages of Coffeescript, the smart subset of JavaScript strict mode, the legendary Emscripten & asm.js combo, the compiler feedback of TypeScript and the performance ambitions of Dart. It’s worth trying out technologies that can leapfrog the current expectations of the user experience that we can deliver. Our web is worth it.

Will Opera be using the Chromium version of Blink wholesale, as far as you know? Are we likely to see some divergence between Opera and Chrome?

As I understand it, Opera Mobile, Opera Desktop, and Opera Mini will all be based on Chromium. This means that they’ll not only share the exact version of Blink that Chrome uses, but also the same graphics stack, JavaScript engine, and networking stack. Already, Opera has contributed some great things to Blink and we’re excited about what’s next.

Why the name “Blink,” anyway?

Haha. Well… it’s a two parter. First, Blink evokes a certain feeling of speed and simplicity—two core principles of Chrome. Then, Chrome has a little tradition of slightly ironic names. Chrome itself is all about minimizing the browser chrome, and the Chromebook Pixel is all about not seeing any pixels at all. So naturally, it fits that Blink will never support the infamous <blink> tag. ;)

<3z

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For ideal typography, web designers need to know as much as possible about each user’s reading environment. That may seem obvious, but the act of specifying web typography is currently like ordering slices of pizza without knowing how large the slices are or what toppings they are covered with.

If someone asked me how many slices of pizza I wanted for lunch, I would probably say it depends on how large the slices are. Then—even if they told me that each slice was one eighth of a whole pie, or that they themselves were ordering two slices, or even that the slices were coming from Joe’s Pizza—any answer I might give would still be based on relative knowledge and inexact assumptions.

Such is the current situation with the physical presentation of responsive typography on the web. The information at a designer’s disposal for responsive design is virtually nonexistent outside the realm of software. Very little knowledge about the physical presentation of content is available to inform the design. The media query features of today can only relay a very fragmented view of the content’s actual presentation, and related terms from CSS are confusing if not downright misleading.

The immeasurable pachyderm

Among all the physical qualities of web typography, the elephant in the room is the issue of size. I’m not talking about em or rem or “reference pixels” ¹ or even device pixels. I’m talking about real, actual, physical, bona fide, measurable, size!

It’s ridiculous that we can send robots to Mars yet it’s still virtually impossible to render a glyph on a web page and say with confidence: “If you measure this glyph on your screen with a ruler, it will be exactly 10 millimeters wide.” Although actual physical size isn’t always the most important factor in web design, in some cases it is critical. For example, consider content for partially-sighted or low-vision readers: the ability to tweak designs according to physical sizes would enable designers to make conscious design decisions with much more sensitivity to how the type is actually being seen. And even where physical sizing is secondary to relative sizing, why shouldn’t we nevertheless be able to factor in physical size when establishing the relationships between different elements?

Physical considerations ≠ print design

I don’t believe web typography should be a screen-based imitation of print typography. One of the greatest benefits of web typography, and web design in general, is that it is flexible, adaptable, fluidly adjustable, without being locked into any one specific configuration. However(!), that doesn’t mean web designers should be forced to design without any means to address the issues of physical presentation. On the contrary, responsive design will not reach its full potential until it allows the ability to respond to the very important physical variables of digital media.

Please pardon the cliché, but when it comes to typography, on screens or otherwise, size matters. Physical size affects optical issues that change how the eye and brain process typographic images. Not surprisingly, typographers and typeface designers have been compensating for optical size-related issues as far back as Gutenberg.

You can’t expect a paragraph of type with the same relative line-height, column width, letter-spacing, and glyph proportions to function just as well on two different displays that have the same number of pixels but completely different physical sizes. It’s great that designers can adjust proportions between typographic elements if the canvas varies in relative size, but any such compensation is still based on guesswork and assumptions about the physical size of that canvas. When people disagree about the size or spacing of type on a website, there’s a very good chance that their opinions are based on completely different physical manifestations of the same content, even if their software and settings are identical.

Resolute resolution, absolute absolution

One of the most crucial factors in the size equation is resolution. And when I say resolution, I don’t just mean “how many pixels is this?”, or even “how many device pixels is this?”, but also “how large are these pixels?”

This is very different from the W3C’s “resolution” media feature in the current draft of the Media Queries Level 4 spec. You will note that the spec refers to resolution in terms of “CSS ‘inches’”—the quotes around “inches” are theirs, implying that they are not actually inches at all.

For an example of why physical resolution matters, imagine you are rendering text on a digital billboard with a physical resolution of one pixel per inch (1 PPI). Now imagine you are rendering the same text on a 200 PPI mobile device display. Even if you knew the actual number of device pixels that would be used to render your type (which itself is difficult to do with confidence these days), you would want to treat the two compositions very differently, both in terms of the typeface as well as typographic layout. The billboard type would likely require less space between letters. The letterforms themselves would benefit from narrower proportions, and could endure a higher ratio between thick and thin strokes. The type might even require different colors to optimize contrast at that size. These are all basics of typography and typeface design.

Unfortunately, in the current landscape of media query features, there is no way to know the difference between 16 device pixels on a crude LED billboard and 16 device pixels on a high-density mobile display. Heck, there isn’t even a reliable way to know if your type is 16 device pixels at all, regardless of how large the pixels are!

Pixels still rule, for better or worse

I know what some em-based enthusiasts might be thinking: “But you shouldn’t be specifying type sizes in pixel units to start with! All type sizes should be spec’d abstractly in relation to each other or a base font size!” However, in the current world of web typography, no matter what unit of measure you use to spec your onscreen type sizes—em, rem, px, pt, in, %, vh, or whatever else—at the end of the line, your specification is being mapped to pixels. Even if you leave the base size of your document to the defaults and specify everything else with em, there is still a base size which all other sizes will ultimately refer to, and it is defined in pixels.

This is because, currently, the only unit of measure that can be rendered onscreen by any operating system with absolute confidence is the lowly pixel. Until we have media query features that allow us to spec for situations like:

@media (physical-resolution: 1device-pixels-per-physical-inch) { … }

or:

@media (device-width: 10physical-centimeters) { … }

… any compensation for physical size is based entirely on rough guesses about the devices our content will be presented on.²

It’s a complete fallacy that the official CSS spec allows so-called “absolute” units of measure like inches, points, and centimeters to be mapped to anything but actual physical units. Ironically, previous versions of CSS treated these things as you would hope and expect, but a change was made “because too much existing content relies on the assumption of 96dpi, and breaking that assumption breaks the content.” Call me idealistic if you will, but I am more of the mind that a spec should be written based on what is best for the future, not to cater to things that were made in the past.³

Getting physical

Any ability to leverage physical variables for web design will require a joint effort by several groups:

  • Device manufacturers will need to provide APIs that can inform the operating system—and, by extension, web browsers and web designers—of the actual physical properties of the hardware being used to present content to the user. Some device APIs are already beginning to show up in the world, but there is a long way to go before functionality and adoption are anywhere near dependable.
  • Standards organizations—the W3C in particular—will need to establish specifications for how to reference physical properties when formatting content. They will need to update (or at least augment) their existing “absolute” units of measure to be more meaningful, so they are more than just multipliers of sizeless pixels.
  • Software manufacturers will need to implement support for new specs relating to physical media features. Browsers are the most obvious software that will need to implement support, but the biggest challenge might be in getting native support for device APIs in operating system software.
  • Type manufacturers and type services will need to provide more diverse ranges of typefaces that have been optimized for a variety of physical properties. Ideally, many of the needed variations could even be provided on the fly using a broader approach to the ideas of font hinting.
  • Web designers and developers, last but not least, will need to build their sites to respond to physical properties, leveraging all variables to the benefit of their users.

Size and resolution are just the tip of the iceberg of physical variables that could be considered when improving web typography. Things like viewing distance, ambient light, display luminance, contrast ratio, black levels, etc., etc., could all be factored in to improve the reading experience. Even the ability to know some variables within the realm of software, like the user’s rendering engine or the presence of subpixel positioning, would go a long way toward helping web typographers design a better reading experience.

In the meantime, I’d love to see more of the players mentioned above start to at least experiment with what’s possible when physical features can be specified, detected, and factored into responsive designs in structured, meaningful, and predictable ways. Until we can do that, we’re all just ordering pizza without knowing exactly what will end up on our plate.

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