Ajax = {
	http:false,
	creatRequest:function(){
		if(window.XMLHttpRequest){
			this.http = new XMLHttpRequest();
			if(this.http.overrideMimeType){
				this.http.overrideMimeType('text/xml');
			}
		}else if(window.ActiveXObject){
			try{
				this.http = new ActiveXObject('Msxml2.XMLHTTP');
			}catch(e){
				try{
				   this.http = new ActiveXObject('Microsoft.XMLHTTP');
				}catch(e){
					this.http = false;
				}
			}
		}
		if(!this.http){
			window.alert('创建 XMLHttpRequest 对象失败.');
			return false;
		}
	},
	sendRequest:function(url,fun){
		this.creatRequest();
		this.http.onreadystatechange = fun;
		this.http.open("GET",url,true);
		this.http.setRequestHeader("If-Modified-Since","0");
		this.http.setRequestHeader("Cache-Control","no-cache");
		this.http.send(null);
	},
	processRequest:function(id){
	  if(this.http.readyState == 4){
		  if(this.http.status == 200){
			  document.getElementById(id).innerHTML = this.http.responseText;
		  }else{
			  return false;
		  }
	  }
  }
}