javascript event事件再次封装了，兼容大多数浏览器

修改记录：

1.整个封装了下，在Event名字空间下

2.代码规范了下

3.增加了cache

4.把原来一个全局变量改了，也放在了Event名字空间下

DEMO下载地址：/Files/sniper007/IEEVENT-version2.rar

上代码

var extend = function(destination,source){
for(var o in source)
destination[o] = source[o];
return destination;
};

(function(){
var Event = {},
Cache,
cache = [],
_onunloadHandlerRegistered;

function addEvent(element, eventType, handler){
if (element.addEventListener) {
element.addEventListener(eventType, handler, false);
} else if (element.attachEvent) {
element.attachEvent("on" + eventType, handler);
} else {
element["on" + eventType] = handler;
}
}

function removeEvent(element, eventType, handler){
if(element.removeEventListener) {
element.removeEventListener(eventType, handler, false);
}else if(element.detachEvent) {
element.detachEvent("on" + eventType, handler);
}else{
element["on" + eventType] = null;
}
}

function getUUID(){
var _counter = 35;
return function(){
return "tigerEvent0" + _counter++;
}
}

function getDoc(element){
return element.ownerDocument || element.document || ((element.defaultView || element.window) && element) || document;
};

function add(element, eventType, handler, list){
var d = getDoc(element),
w = cache,
id = getUUID();

w[id] = list;
if(!element._handlers){
element._handlers = [];
}
element._handlers.push(id);
}

function get(element, eventType, handler, isSignal){
var handlers = element._handlers,
returnVal = -1,
returnObj = null;
if(!handlers){
return -1;
}
var d = getDoc(element),
w = cache;
for(var i = handlers.length - 1; i >= 0; i--){
var handlerId = handlers[i],
h = w[handlerId];
if(h.eventType == eventType && h.handler == handler){
returnVal = i;
returnObj = h;
break;
}
}
if(!!isSignal){
return [returnVal, returnObj];
}else{
return -1;
}
}

function remove(element, eventType, handler){
var i = find(element, eventType, handler);
if(i == -1){
return;
}
var d = getDoc(element),
w = cache,
handlerId = element._handlers[i],
h = w[handlerId];
element._handlers.splice(i, 1);
delete cache[handlerId];
}

function on(element, eventType, handler){
var i = get(element, eventType, handler);
if(i != -1){
return;
}
function wrappedHandler(e){
e = window.event || e;
var event = fixed(e);
event._event = e;
handler.call(element, event);
}

var h = {
element : element,
eventType : eventType,
handler : handler,
wrappedHandler : wrappedHandler
};
add(element, eventType, handler, h);
addEvent(element, eventType, h.wrappedHandler);

if(!_onunloadHandlerRegistered){
_onunloadHandlerRegistered = true;
if(window.attachEvent){
window.attachEvent("onunload", removeAllHandlers);
}
}
}

function un(element, eventType, handler){
var i = get(element, eventType, handler);
if(i != -1){
return;
}
removeEvent(element, eventType, get(element, eventType, handler, true).wrappedHandler);
element._handlers.splice(i, 1);
remove(element, eventType, handler);
}

function fixed(event){
if ( !event.target ) {
event.target = event.srcElement || document;
}
if ( event.target.nodeType === 3 ) {
event.target = event.target.parentNode;
}

if ( !event.relatedTarget && event.fromElement ) {
event.relatedTarget = event.fromElement === event.target ? event.toElement : event.fromElement;
}

if ( event.pageX == null && event.clientX != null ) {
var eventDocument = event.target.ownerDocument || document,
doc = eventDocument.documentElement,
body = eventDocument.body;

event.pageX = event.clientX + (doc && doc.scrollLeft || body && body.scrollLeft || 0) - (doc && doc.clientLeft || body && body.clientLeft || 0);
event.pageY = event.clientY + (doc && doc.scrollTop || body && body.scrollTop || 0) - (doc && doc.clientTop || body && body.clientTop || 0);
}

if ( event.which == null && (event.charCode != null || event.keyCode != null) ) {
event.which = event.charCode != null ? event.charCode : event.keyCode;
}

if ( !event.metaKey && event.ctrlKey ) {
event.metaKey = event.ctrlKey;
}
if ( !event.which && event.button !== undefined ) {
event.which = (event.button & 1 ? 1 : ( event.button & 2 ? 3 : ( event.button & 4 ? 2 : 0 ) ));
}

return event;
}

function fire(element, eventType){
if (document.dispatchEvent) {
var evt = null,
doc = getDoc(element);
if (/mouse|click/i.test(eventType)) {
evt = doc.createEvent('MouseEvents');
evt.initMouseEvent(eventType, true, true, doc.defaultView, 1, 0, 0, 0, 0, false, false, false, false, 0, null);
} else {
evt = doc.createEvent('Events');
evt.initEvent(eventType, true, true, doc.defaultView);
}
element.dispatchEvent(evt);
}else{
element.fireEvent('on' + eventType);
}
}

/*
防止IE内存溢出
*/

function removeAllHandlers(){
var w = cache;
for(var id in w){
var h = w[id];
if(h.element.detachEvent){
h.element.detachEvent("on" + h.eventType, h.wrappedHandler);
}
delete w[id];
}
}

extend(Event, {
on : on,
un : on,
fire : fire,
cache : cache,
addEvent : addEvent,
removeEvent : removeEvent,
_onunloadHandlerRegistered : _onunloadHandlerRegistered
});

window.Event = Event;
})();