Callback on CSS transition

Is it possible to get a notification (like callback) when a CSS transition has been completed?

Yes, if such things are supported by the browser, then an event is triggered when the transition completes. The actual event however, differs between browsers:

• Webkit browsers (Chrome, Safari) use webkitTransitionEnd
• Firefox uses transitionend
• IE9+ uses msTransitionEnd
• Opera uses oTransitionEnd

However you should be aware that webkitTransitionEnd doesn't always fire! This has caught me out a number of times, and seems to occur if the animation would have no effect on the element. To get around this, it makes sense to use a timeout to fire the event handler in the case that it's not been triggered as expected. A blog post about this problem is available here: http://www.cuppadev.co.uk/the-trouble-with-css-transitions/ <-- 500 Internal Server Error

With this in mind, I tend to use this event in a chunk of code that looks a bit like this:

var transitionEndEventName = "XXX"; //figure out, e.g. "webkitTransitionEnd".. 
var elemToAnimate = ... //the thing you want to animate..
var done = false;
var transitionEnded = function(){
     done = true;
     //do your transition finished stuff..
     elemToAnimate.removeEventListener(transitionEndEventName,
                                        transitionEnded, false);
};
elemToAnimate.addEventListener(transitionEndEventName,
                                transitionEnded, false);

//animation triggering code here..

//ensure tidy up if event doesn't fire..
setTimeout(function(){
    if(!done){
        console.log("timeout needed to call transition ended..");
        transitionEnded();
    }
}, XXX); //note: XXX should be the time required for the
        //animation to complete plus a grace period (e.g. 10ms) 

Note: to get the transition event end name you can use the method posted as the answer in: How do I normalize CSS3 Transition functions across browsers?.

Note: this question is also related to: - CSS3 transition events

I know that Safari implements a webkitTransitionEnd callback that you can attach directly to the element with the transition.

Their example (reformatted to multiple lines):

box.addEventListener( 
     'webkitTransitionEnd', 
     function( event ) { 
         alert( "Finished transition!" ); 
     }, false );

I am using the following code, is much simpler than trying to detect which specific end event a browser uses.

$(".myClass").one('transitionend webkitTransitionEnd oTransitionEnd otransitionend MSTransitionEnd', 
function() {
 //do something
});

Alternatively if you use bootstrap then you can simply do

$(".myClass").one($.support.transition.end,
function() {
 //do something
});

This is becuase they include the following in bootstrap.js

+function ($) {
  'use strict';

  // CSS TRANSITION SUPPORT (Shoutout: http://www.modernizr.com/)
  // ============================================================

  function transitionEnd() {
    var el = document.createElement('bootstrap')

    var transEndEventNames = {
      'WebkitTransition' : 'webkitTransitionEnd',
      'MozTransition'    : 'transitionend',
      'OTransition'      : 'oTransitionEnd otransitionend',
      'transition'       : 'transitionend'
    }

    for (var name in transEndEventNames) {
      if (el.style[name] !== undefined) {
        return { end: transEndEventNames[name] }
      }
    }

    return false // explicit for ie8 (  ._.)
  }

  // http://blog.alexmaccaw.com/css-transitions
  $.fn.emulateTransitionEnd = function (duration) {
    var called = false, $el = this
    $(this).one($.support.transition.end, function () { called = true })
    var callback = function () { if (!called) $($el).trigger($.support.transition.end) }
    setTimeout(callback, duration)
    return this
  }

  $(function () {
    $.support.transition = transitionEnd()
  })

}(jQuery);

The jQuery.transit plugin, a plugin for CSS3 transformations and transitions, can call your CSS animations from script and give you a callback.

This can easily be achieved with the transitionend Event see documentation here A simple example:

document.getElementById("button").addEventListener("transitionend", myEndFunction);

function myEndFunction() {
	this.innerHTML = "Transition event ended";
}

#button {transition: top 2s; position: relative; top: 0;}

<button id="button" onclick="this.style.top = '55px';">Click me to start animation</button>