Responsive web design is a term used to describe a web design that adapts itself to the end-user’s environment. This isn’t a new concept, but advancements in browser technology as well as a greater increase in viewing environment (desktop, netbook, smartphone, etc.) is allowing for some new and interesting tricks to our bag.
Responsive web design is something that’s been around since the first web designs came out utilizing percent values to define the widths of objects, such as TABLE, DIV, and IMG elements. The idea was that a person on a 640×480 resolution screen can view the web site, but a person with a larger resolution like 1024×768 would be able to see more content on their screen as the layout would expand to the edges of the larger viewport (the area in which a web page is rendered). This idea was somewhat radical back in the early 1990s as most layouts would simply set a fixed width for the layout (usually 780 or 1000 pixels) and state quite plainly on the web site that it was designed to be “best viewed in 1024×768”.
Things got more interesting with CSS. Web designs could now use percentages for margins, padding, and placement of elements within a page. Layouts that would expand and contract with the viewport could be more complicated. Especially handy were the CSS max-width and min-width attributes. These allowed you to set limits on just how much your layout would expand or contract before forcing the viewport to stop resizing the layout. Now layouts could expand and contract, but not so much that they became unusable.
Enter CSS3 media queries.
But first, a small caveat to web developers.
The CSS3 spec is not yet final. In fact there isn’t (or is, depending on your point of view) really a CSS3 spec at all. CSS3 is a collection of modules and therefore somewhat open-ended. You can see a list of some of the CSS3 modules and their curren status here. Some CSS3 modules are currently in an early format and not recommended for implementation, while others have reached a state where it’s not quite final, but browser authors are encouraged to implement these modules and supply feedback to help refine the spec before it becomes final. Media queries are in such a state and as such several modern browsers have already implemented them including the latest releases of Firefox, Chrome, Safari and Opera. So web developers can start making use of them now and those users who run modern web browsers will be able to enjoy your use of CSS3.
At the same time, I do not recommended you rely heavily on CSS3 modules in any designs for the near future, or that if you do, you do so while making sure to check compatibility of the layout against older browsers. While the general public appears to be more capable at keeping up to date with their browser (mainly thanks to the automated update features of several OSes and the increased proliferation of broadband internet connections), there’s still a significant number of users (over 50% according to this site) who are using Internet Explorer 8 or earlier, which does not support media queries (or much else in the way of CSS3). IE9 will support media queries.
Now that that’s out of the way, what can media queries do for us? Simply stated, you can apply styles based on many attributes of the viewport. To keep things brief-ish and to the point, I’m going to specifically focus on width-related media queries. Let’s see what one looks like:
#frame { width: 1000px; margin: 0 auto; }
@media screen and ( max-width: 480px ) {
#frame {
width: 100%;
}
}
The above example will make an element with the id of “frame” to be 1,000 pixels wide and will center (via the margin value auto for the left and right margin properties) it in the middle of the viewport if the viewport is wider than 1,000 pixels. On the second line is a media query. It begins with @media screen (in place of “screen” you can use “all” for any media, or “print” for print media, etc.) which lets the browser know that the following block of CSS should only be applied to the screen. This is followed by and ( max-width: 480px ) which is the media query. It states that the following block of rules should also only be applied when the viewport is at or less than 480 pixels in width. You can also use min-width to tell the browser the block of rules should only be applied when the viewport is at least 480 pixels wide.
Why would you want such a thing? If a viewport is that narrow and you have wide elements or you have multiple columns, chances are those elements would be very usable at such a narrow width. With a media query you can change the layout to something more usable on a small screen. For example, consider a layout that has multiple columns. At 480 pixels your columns will barely fit a few words per line, if any at all. Reading text becomes very difficult. With a media query you can drop your multiple columns into a single column layout. Now each column will have the full width of the viewport to render its content, making it much more usable.
In the example above I am removing the fixed-width on the #frame element and resetting its width to 100% of the viewport. Smartphone users will be able to view the content of the layout much more easily and without having to scroll horizontally to read each line.
Excellent! Now go and design for the masses!
But… not quite yet. There’s one problem. Some smartphones are a bit too smart. They understand not many web designs are out there that take advantage of these features. Instead these smartphones will scale the rendering of the page. While the screen may only have 480 pixels of width, it’ll render web pages as if it had 1024 pixels of width and then scale it down to fit the screen. Media queries alone won’t fix this problem.
However, there is a solution.
The viewport meta tag allows you to tell browsers how to scale the web page. Most mobile browsers understand this tag including the mobile version of Safari found on may Apple devices and the mobile version of Opera which is found just about everywhere else. So to fix the mobile browser scaling issues, just include the following META tag into your web page:
<meta name="viewport" content="width=device-width; initial-scale=1.0;">
This tag tells the browser to render the web page with a 1-to-1 pixel scaling. Meaning 1 pixel of your web site is 1 pixel on the device’s screen. There are many other attributes you can include in this META tag such as maximum and minimum scaling values or whether the user is allowed to scale the page. Disabling user scaling effectively disables the pinch-zoom feature of many mobile devices. I recommend against it.
One last thing to touch upon before I give you a working example. It’s a simple block of CSS that will help make everything run much more smoothly on a mobile browser:
img { max-width: 100%; }
This little CSS rule allows images to shrink as needed as their containing element shrinks. So a 600 pixel wide image will shrink enough to fit on a 480 pixel wide browser. It’s a cheap, but very useful trick. However I would suggest that you don’t use the exact CSS rule given above. To apply such a thing to all images may have unexpected negative effects on images that you don’t want to have shrink as needed. Instead use a more specific CSS selector such as
#frame .blog-post .post-content img { max-width: 100%; }
The more specific you are, the less surprises you’ll have down the road.
As promised, I have put together a demonstration web page that utilizes all these techniques. Grab a modern browser that isn’t Internet Explorer, open the layout, and start shrinking and growing your browser’s window to see the content and layout change to fit within the width of your window. Pop it open on your smartphone’s browser as well!
MARS: Responsive Layout Demo
The stylesheet is embedded in the source to encourage you to take a look at the whole source for the page. It has also been given some CSS hacks so that the layout will work even in IE 7 and IE 6 (in theory), but all the media query stuff will obviously not work.
One final note.
At home I have a very wide (16:10) monitor, while at work I have a standard (4:3) monitor. I like to set max-widths to my layouts because keeping the distance from end to end of a given line of text small helps reduce eyestrain and the whitespace on either side of the layouts is more visually pleasing. But on a very wide monitor, the whitespace on the sides is too much and it makes the layout look very small. With media queries I can fix this problem by increasing the max-width of my layout frame for those screens with a very large width (over 1280 pixels). I could also increase the font size to help with readability. The point is that media queries aren’t just for keeping your pages usable on a smartphone, but they also help keep them usable on very large screens as well.
The Forgettable Mister Ruthsarian 