/**
 * addEvent written by Dean Edwards, 2005
 * with input from Tino Zijdel
 *
 * http://dean.edwards.name/weblog/2005/10/add-event/
 * licensed under http://creativecommons.org/licenses/by/2.5/
 **/
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;
};

// end from Dean Edwards


/**
 * Creates an Element for insertion into the DOM tree.
 * From http://simon.incutio.com/archive/2003/06/15/javascriptWithXML
 *
 * @param element the element type to be created.
 *              e.g. ul (no angle brackets)
 **/
function createElement(element) {
    if (typeof document.createElementNS != 'undefined') {
        return document.createElementNS('http://www.w3.org/1999/xhtml', element);
    }
    if (typeof document.createElement != 'undefined') {
        return document.createElement(element);
    }
    return false;
}

/**
 * "targ" is the element which caused this function to be called
 * from http://www.quirksmode.org/js/events_properties.html
 * see http://www.quirksmode.org/about/copyright.html
 **/
function getEventTarget(e) {
    var targ;
    if (!e) {
        e = window.event;
    }
    if (e.target) {
        targ = e.target;
    } else if (e.srcElement) {
        targ = e.srcElement;
    }
    if (targ.nodeType == 3) { // defeat Safari bug
        targ = targ.parentNode;
    }

    return targ;
}