// addEvent/removeEvent 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;
};

function domReady( f ) {
    // If the DOM is already loaded, execute the function right away
    if ( domReady.done ) return f();

    // If we’ve already added a function
    if ( domReady.timer ) {
        // Add it to the list of functions to execute
        domReady.ready.push( f  );
    } else {
        // Attach an event for when the page finishes  loading,
        // just in case it finishes first. Uses addEvent.
        addEvent( window, "load", isDOMReady );

        // Initialize the array of functions to execute
        domReady.ready = [ f ];

        //  Check to see if the DOM is ready as quickly as possible
        domReady.timer = setInterval( isDOMReady, 13 );
    }
}

// Checks to see if the DOM is ready for navigation
function isDOMReady() {
    // If we already figured out that the page is ready, ignore
    if ( domReady.done ) return false;

    // Check to see if a number of functions and elements are
    // able to be accessed
    if ( document && document.getElementsByTagName && 
          document.getElementById && document.body ) {

        // If they’re ready, we can stop checking
        clearInterval( domReady.timer );
        domReady.timer = null;

        // Execute all the functions that were waiting
        for ( var i = 0; i < domReady.ready.length; i++ )
            domReady.ready[i]();

        // Remember that we’re now done
        domReady.ready = null;
        domReady.done = true;
    }
}