用setTimeout模拟setInterval的功能

//用setTimeout模仿setInterval
var MyInterVal = function(fun,tm){
if(this == window){
return new MyInterVal(fun,tm);
}
this.Fun = null;
this.id = -1;this.clear = function(id){
clearTimeout(this.id);
}
this.setInterval = function(_fun,_tm){
var self = this;
if(this.Fun==null){
if(typeof _fun=="string"){
this.Fun = new Function(_fun);
}else if(typeof _fun=='function'){
this.Fun = _fun;
}
}
this.id = setTimeout(function(){
self.Fun();
self.setInterval(self.Fun,_tm);
},tm);
}
this.setInterval(fun,tm);
}//使用方法一
var s = MyInterVal(function(){
console.log();
},);//使用方法二
var s = MyInterVal("console.log(1)",1000)setTimeout(function(){
s.clear();//清除
},)