<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title> 自定义事件 </title>
</head>
<body>
</body>
</html>
<script>
function EventTarget(){
this.handlers = {};
}
EventTarget.prototype = {
constructor : EventTarget,
// 注册事件
addHandler : function(type,handler){
if(typeof this.handlers[type] == 'undefined') this.handlers[type] = [];
this.handlers[type].push(handler);
},
// 触发事件
fire : function(event){
if(!event.target) event.target = this;
if(this.handlers[event.type] instanceof Array){
var handlers = this.handlers[event.type];
for(var i=0,len=handlers.length;i<len;i++){
handlers[i](event);
}
}
},
// 移除事件
removeHandler : function(type,handler){
if(this.handlers[type] instanceof Array){
var handlers = this.handlers[type];
for(var i=0,len=handlers.length;i<len;i++){
if(handlers[i] == handler) break;
}
handlers.splice(i,1);
}
}
}
function fn_message(event){
alert(event.message);
}
var target = new EventTarget();
target.addHandler('message',fn_message);
target.fire({type:'message',message:'I love javascript'});
target.removeHandler('message',fn_message);
target.fire({type:'message',message:'I love javascript'});
</script>
