Stagger events across a collection of elements

jquery.staggeredEvent.js

/*
Stagger an event across a collection of elements. Useful for making the pretties.

Example - for loading in ajax results with a class-based css3 transition, where results are initially hidden with hide():
$('#ajax-results').on('loaded', function(){
  $(this).children('.result').addClass('pre-transition').slideDown(250).staggerEvent(function(el){
    $(el).removeClass('pre-transition');
  }, 150, 250);
});
*/
$.fn.staggerEvent = function(ev, delay, initialDelay){
  var ev = ev, delay = delay, $els = $(this);
  if(typeof initialDelay === 'undefined') initialDelay = 0;
  setTimeout(function(){
    $els.each(function(i){
      var $this = $(this);
      setTimeout(function(){
        if(typeof ev === 'function') {
          ev($this);
        } else {
          $this.trigger(ev);
        }
      }, delay * i);
    });
  }, initialDelay);
  return $(this);
};