code: function(type, fn, details) {
          return this.each(function (el) {
              if (xui.events[type]) {
                  var id = _getEventID(el), 
                      responders = _getRespondersForEvent(id, type);
                  
                  details = details || {};
                  details.handler = function (event, data) {
                      xui.fn.fire.call(xui(this), type, data);
                  };
                  
                  // trigger the initialiser - only happens the first time around
                  if (!responders.length) {
                      xui.events[type].call(el, details);
                  }
              } 
              el.addEventListener(type, _createResponder(el, type, fn), false);
          });
      }
docs: on
  --
  
  Registers a callback function to a DOM event on the element collection.
  
  ### syntax ###
  
  x$( 'button' ).on( type, fn );
  
  or
  
  x$( 'button' ).click( fn );
  
  ### arguments ###
  
  - type `String` is the event to subscribe (e.g. _load_, _click_, _touchstart_, etc).
  - fn `Function` is a callback function to execute when the event is fired.
  
  ### example ###
  
  x$( 'button' ).on( 'click', function(e) {
  alert('hey that tickles!');
  });
  
  or
  
  x$(window).load(function(e) {
  x$('.save').touchstart( function(evt) { alert('tee hee!'); }).css(background:'grey');
  });