Retrieving requestAnimationFrame with JavaScript
The requestAnimationFrame function has been a major boost to developers creating and managing animations with JavaScript. Paul Irish has an excellent introduction on requestAnimationFrame -- I highly recommend you read it. This HTML5Hub post is also very good. Most browsers now support the animation function but in the case a browser doesn't, you can shim a rough equivalent with setInterval:
var requestAnimationFrame = window.requestAnimationFrame
|| window.webkitRequestAnimationFrame
|| window.mozRequestAnimationFrame
|| window.msRequestAnimationFrame
|| function(callback) { return setTimeout(callback, 1000 / 60); };
requestAnimationFrame was implemented with browser prefixes so we'll check for those if the unprefixed window method isn't there. If no native implementation exists, a setInterval shim will have to do!
![Create Namespaced Classes with MooTools]()
MooTools has always gotten a bit of grief for not inherently using and standardizing namespaced-based JavaScript classes like the Dojo Toolkit does. Many developers create their classes as globals which is generally frowned up. I mostly disagree with that stance, but each to their own. In any event...
![Conquering Impostor Syndrome]()
Two years ago I documented my struggles with Imposter Syndrome and the response was immense. I received messages of support and commiseration from new web developers, veteran engineers, and even persons of all experience levels in other professions. I've even caught myself reading the post...
![Facebook Sliders With Mootools and CSS]()
One of the great parts of being a developer that uses Facebook is that I can get some great ideas for progressive website enhancement. Facebook incorporates many advanced JavaScript and AJAX features: photo loads by left and right arrow, dropdown menus, modal windows, and...
![Build a Calendar Using PHP, XHTML, and CSS]()
One of the website features my customers love to provider their web users is an online dynamic calendar. An online calendar can be used for events, upcoming product specials, memos, and anything else you can think of. I've taken some time to completely...
According to caniuse, Microsoft’s browsers never had a vendor prefixed version of
requestAnimationFrame, so we can just keepmozandwebkit.That’s a very common way to normalize the function, but in most recent implementations
requestAnimationFramepasses an argument to the callback function, which is the amount of milliseconds sinceperformance.timing.navigationStart, with micro precision too. This can be very handy for the callback.It’s not really possible to perfectly emulate this, but you can get something close if you take note of the epoch time as soon as the script is executed. So this is how I used to polyfill
requestAnimationFrame:(function(start) { window.requestAnimationFrame = function(callback) { return setInterval(function() { callback(new Date().getTime() - start); }, 1000 / 60); }; })(new Date().getTime());(Well, not exactly… since most of the times
requestAnimationFrameis called again in the callback function, but the function itself takes some milliseconds at least to be executed – because it probably involves some kind of repaint – and you should adjust the time interval accordingly, or you may never hope to even get close to 60 fps.)Also, don’t forget to normalize
cancelAnimationFrame, which has a nasty variant in some (and maybe forgotten?) WebKit browsers:webkitCancelRequestAnimationFrame.