gistfile1.js

// 
// The logic here is the transitionend event fires instantly
// after the transition is done (1ms here). I have seen timeouts
// taking up to 300ms to fire (!) so the main avantage is responsiveness.
// 
window.requestTimeout = (function(){
  var vendors = 'Webkit Moz O ms Khtml'.split(' '),
  supports = (function() {  
     var div = document.createElement('div'),  
        len = vendors.length;  
     return function(prop) {  
        if ( prop in div.style ) return true;  
        prop = prop.replace(/^[a-z]/, function(val) {  
          return val.toUpperCase();  
        });  
        while(len--) {  
          if ( vendors[len] + prop in div.style ) {  
            return true;  
          }  
        }  
        return false;  
     };  
  })(); 
  var gotAnimations = supports("transition"),
  $to = $("#timeout" ), callbacks = [], stopped = true;
  
  if(gotAnimations){
    $to.on("transitionend webkitTransitionEnd oTransitionEnd otransitionend", function(){

      Em.run(function(){
        while(callbacks.length > 0){
          var cb = callbacks.pop();
          cb.call(window);
        }
      });

      if(callbacks.length > 0){
        $to.hasClass("in") ? $to.removeClass("in") : $to.addClass("in");
      }else{
        stopped = true;
      }
    });
  }

  return function(callback, t){
    if(gotAnimations ){
      callbacks.push(callback);
      if(stopped){
        stopped = false;
        $to.hasClass("in") ? $to.removeClass("in") : $to.addClass("in");
      }
    }else{
      window.setTimeout(function(){
        Em.run(function(){
          callback.call(t || this);
        });
      }, 0);
    }
  };
})();