// written by Dean Edwards, 2005
// with input from Tino Zijdel - crisp@xs4all.nl
// http://dean.edwards.name/weblog/2005/10/add-event/
// Tino's input: http://therealcrisp.xs4all.nl/upload/addEvent_dean.html
function addEvent(element, type, handler) {
   if (element.addEventListener)
      element.addEventListener(type, handler, false);
   else {
      if (!handler.$$guid) handler.$$guid = addEvent.guid++;
      if (!element.events) element.events = {};
      var handlers = element.events[type];
      if (!handlers) {
         handlers = element.events[type] = {};
         if (element['on' + type]) handlers[0] = element['on' + type];
         element['on' + type] = handleEvent;
      }
   
      handlers[handler.$$guid] = handler;
   }
}
addEvent.guid = 1;

function removeEvent(element, type, handler) {
   if (element.removeEventListener)
      element.removeEventListener(type, handler, false);
   else if (element.events && element.events[type] && handler.$$guid)
      delete element.events[type][handler.$$guid];
}

function handleEvent(event) {
   event = event || fixEvent(window.event);
   var returnValue = true;
   var handlers = this.events[event.type];

   for (var i in handlers) {
      if (!Object.prototype[i]) {
         this.$$handler = handlers[i];
         if (this.$$handler(event) === false) returnValue = false;
      }
   }

   if (this.$$handler) this.$$handler = null;

   return returnValue;
}

function fixEvent(event) {
   event.preventDefault = fixEvent.preventDefault;
   event.stopPropagation = fixEvent.stopPropagation;
   return event;
}
fixEvent.preventDefault = function() {
   this.returnValue = false;
}
fixEvent.stopPropagation = function() {
   this.cancelBubble = true;
}

// This little snippet fixes the problem that the onload attribute on the body-element will overwrite
// previous attached events on the window object for the onload event
if (!window.addEventListener) {
   document.onreadystatechange = function() {
      if (window.onload && window.onload != handleEvent) {
         addEvent(window, 'load', window.onload);
         window.onload = handleEvent;
      }
   }
}