When you hear slideshow, you probably think of Javascript, maybe via your favorite framework or not.

Well, those days are over. HTML5 is more and more present, and yes, you should begin learning it. Today, we are gonna focus on a very specific feature called keyframes.


Keyframes let you define animation appearances in pure CSS. Those are broken down into:

  • steps - expressed in percentage (e.g. 0%, 33%, 66%, 100%). Note that from and to can be respectively used in lieu of 0% and 100%.

  • effects - each step defines a set of CSS rules.

@keyframes AnimationName {
    0%,15%,100% {left: 0px;}
    35%,50% {left: -640px;}   
    70%,85% {left: -1280px;}

In the above example, nothing fancy: this animation does no more than moving the attached block to the left and come back to its initial position (provided this element is positioned relatively to one of its parents). By the way, be wary of keyframes browser support. Indeed, you might need to prefix your keyframes rules by your target browser vendor prefix.

Animation settings

Now that you have defined the animation appearance, it must be applied to an element and the animation behavior must be set.

Here is an interesting subset of the available animation sub-properties:

  • animation-name: as you guess, this corresponds to the name in the @keyframes declaration (here: AnimationName) ;

  • animation-duration: the number of seconds to complete one cycle (basically, from 0 to 100%) ;

  • animation-iteration-count: how many time the keyframe will be played ;

  • animation-timing-function: you can pick up amongst a bunch of predefined functions to describe the timing acceleration curve.

#myElementId {    
    animation-name: AnimationName;   
    animation-duration: 20s;   
    animation-iteration-count: infinite;   
    animation-timing-function: ease-in-out;

In this example, the animation will loop forever, each cycle taking 20 seconds to complete following an ease-in-out curve.

A live example

Cross-browser compatibility

Because HTML5 features are not uniformly supported by browsers, I decided to download HTML5 Boilerplate so to benefit from consistent rendering amongst browsers and devices. I did not explore all the functionalities it brings, but I can already say this is a lightweight and loosely structuring solution that I am most certainly gonna use for other experiments.

Keyframes also suffer from that inconsistent support, I wrote a small and ad-hoc Javascript snippet pretty much inspired from one Mozilla Developer Network article.

var hasKeyFrameSupport = false;
var vendorPrefixes = 'Webkit Moz O ms Khtml'.split(' ');
var slideContainer = document.getElementById('myElementId');
if (!slideContainer.style.animationName) {

    for (var i = 0; !hasKeyFrameSupport && i < vendorPrefixes.length; i++) {
        var animation = vendorPrefixes[i]+'AnimationName';
        hasKeyFrameSupport = (slideContainer.style[animation] !== undefined);

    if (!hasKeyFrameSupport) {
        var upgrade = document.createElement('p');
        upgrade.setAttribute('id', 'upgrade');       
        upgrade.appendChild(document.createTextNode('For better CSS, upgrade your browser!'));

Once again, this is not rocket science. The following script first checks the standard animationName property existence. Then, the script iterates over several vendor-prefixed animation name property just to check if one is supported.

If none of the previous tests succeed, a warning good-tasting message notifies the user that his computer might be stuck in a spatiotemporal distortion causing some deprecated pieces of software to live longer than they should.

lorem ipsum 2.0

Not much to say except that you should check Samuel L. Ipsum out.

esporx labs?!

esporx is a cool project I am working on, on my free time. There is gonna be for sure a full post about it. In short: the new ESPN for esports events, hosted by Google App Engine, powered by Spring MVC and JPA and awesomely rendered by truly awesome webdesigners (and this obviously does not include myself) and HTML5 :)


Check the full example here!