// written by Dean Edwards, 2005
// with input from Tino Zijdel

// http://dean.edwards.name/weblog/2005/10/add-event/

function addEvent(element, type, handler) {
	// assign each event handler a unique ID
	if (!handler.$$guid) handler.$$guid = addEvent.guid++;
	// create a hash table of event types for the element
	if (!element.events) element.events = {};
	// create a hash table of event handlers for each element/event pair
	var handlers = element.events[type];
	if (!handlers) {
		handlers = element.events[type] = {};
		// store the existing event handler (if there is one)
		if (element["on" + type]) {
			handlers[0] = element["on" + type];
		}
	}
	// store the event handler in the hash table
	handlers[handler.$$guid] = handler;
	// assign a global event handler to do all the work
	element["on" + type] = handleEvent;
};
// a counter used to create unique IDs
addEvent.guid = 1;

function removeEvent(element, type, handler) {
	// delete the event handler from the hash table
	if (element.events && element.events[type]) {
		delete element.events[type][handler.$$guid];
	}
};

function handleEvent(event) {
	var returnValue = true;
	// grab the event object (IE uses a global event object)
	event = event || fixEvent(window.event);
	// get a reference to the hash table of event handlers
	var handlers = this.events[event.type];
	// execute each event handler
	for (var i in handlers) {
		this.$$handleEvent = handlers[i];
		if (this.$$handleEvent(event) === false) {
			returnValue = false;
		}
	}
	return returnValue;
};

function fixEvent(event) {
	// add W3C standard event methods
	event.preventDefault = fixEvent.preventDefault;
	event.stopPropagation = fixEvent.stopPropagation;
	return event;
};
fixEvent.preventDefault = function() {
	this.returnValue = false;
};
fixEvent.stopPropagation = function() {
	this.cancelBubble = true;
};


/**
 * Pseudo event handler to be fired after the DOM was parsed or
 * on window load at last.
 *
 * @author based upon some code by Dean Edwards
 * @author Andreas Gohr
 * @see    http://dean.edwards.name/weblog/2005/09/busted/
 */
window.fireoninit = function() {
  // quit if this function has already been called
  if (arguments.callee.done) return;
  // flag this function so we don't do the same thing twice
  arguments.callee.done = true;

	if (typeof window.oninit == 'function') {
		window.oninit();
  }
};

/**
 * This is a pseudo Event that will be fired by the above function
 *
 * Use addInitEvent to bind to this event!
 *
 * @author Andreas Gohr
 */
window.oninit = function(){};

/**
 * Bind a function to the window.init pseudo event
 *
 * @author Simon Willison
 * @see http://simon.incutio.com/archive/2004/05/26/addLoadEvent
 */
function addInitEvent(func) {
  var oldoninit = window.oninit;
  if (typeof window.oninit != 'function') {
    window.oninit = func;
  } else {
    window.oninit = function() {
      oldoninit();
      func();
    };
  }
}