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Event系统 by 司徒正美

<script type="text/javascript教程">
var dom = {};
Array.prototype.indexOf = function (el, index) {
var n = this.length>>>0,
i = index == null ? 0 : index < 0 ? Math.max(0, n + index) : index;
for (; i < n; i++)
if (i in this && this[i] === el) return i;
return -1;
};
//http://msdn.microsoft.com/zh-cn/library/bb383786.asp教程x
//移除 Array 对象中某个元素的第一个匹配项。
Array.prototype.remove= function (item) {
var index = this.indexOf(item);
if (index !== -1) return this.removeAt(index);
return null;
};
//移除 Array 对象中指定位置的元素。
Array.prototype.removeAt= function (index) {
return this.splice(index, 1)
};
dom.attachEvent = function(el, type, handler) {
// 在每个元素上设置一个Object类型的私定义属性events
if (!el.events) el.events = {};
// 这个对象有许多键为事件类型,值为函数数组的属性
var handlers = el.events[type];
if (!handlers) {
handlers = el.events[type] = [];
// 如果它原来就以onXXXX方式绑定了某事件,那么把它置为事件数组的第一个元素
if (el["on" + type]) {
handlers[0] = el["on" + type];
}
}
//添加回调函数
handlers.push(handler)
//以onXXXX方式绑定我们的处理函数
el["on" + type] = dom.handleEvent;
};
dom.detachEvent = function(el, type, handler) {
if (el.events && el.events[type]) {
el.events[type].remove(handler)
}
}
dom.handleEvent = function (event) {
var returnValue = true;
// grab the event object (IE uses a global event object)
event = event || fixEvent(((this.ownerDocument || this.document || this).parentWindow || 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=0,n=handlers.length;i if (handlers[i](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;
};
var $ = function(id){
return document.getElementById(id)
}
window.onload = function(){
var a = function(e){
$("p").innerHTML = e.clientX +" "+e.clientY
}
dom.attachEvent($("target"),"mousemove",a);
setTimeout(function(){
dom.detachEvent($("target"),"mousemove",a);
},10*1000)
}
</script>







dom.handleEvent = function (event) {
event = event || window.event
event = dom.fixEvent(event);
event.currentTarget = this;//修正currentTarget
var returnValue = true;
var handlers = this.events[event.type];
for(var i=0,n=handlers.length;i if (handlers[i](event) === false) {
returnValue = false;
}
}
return returnValue;
};

本文来源:http://www.gdgbn.com/bangongshuma/23898/