var xmlhttp_request = false;
	function createXMLRequester(){ 
		try
		{
			//for Internet Explorer5.0,6.0
			if( window.ActiveXObject )
			{
				xmlhttp_request = new ActiveXObject("MSXML2.XMLHTTP");
				// run regsvr32 msxml3.dll if create failurely
				//xmlhttp_request.setRequestHeader("Content-Type","text/xml"); 
				//xmlhttp_request.setRequestHeader("Content-Type","gb2312");
			}
			//for Mozilla,Netscape,Safari
			else if( window.XMLHttpRequest )
			{ 
				xmlhttp_request = new XMLHttpRequest();
				if (xmlhttp_request.overrideMimeType) 
				{
					xmlhttp_request.overrideMimeType('text/xml'); 
				} 
			} 
		}
		catch(e)
		{ 
			xmlhttp_request = false; 
		}
		return xmlhttp_request;
	}
	//readyState:	
	//0 (uninitiatal) 
	//1 (loading...) 
	//2 (loaded!) 
	//3 (interactiving...) 
	//4 (finished!)	
	function sendRequest(url_request,callbackFun)
	{
		xmlhttp_request= createXMLRequester();		
		xmlhttp_request.onreadystatechange = callbackFun;		
		//附加currentTime参数的目的是每次调用的url不一样，便于去除浏览器缓存的影响
		url_request = url_request + "&currentTime=" + new Date();
		xmlhttp_request.open('GET', url_request, true); 
		xmlhttp_request.send(null); 
	}
	
	//readyState:	
	//0 (uninitiatal) 
	//1 (loading...) 
	//2 (loaded!) 
	//3 (interactiving...) 
	//4 (finished!)	
	function sendEncodedRequest(url_request,argArray,callbackFun)
	{
		var length = argArray.length;
		for(var i=0;i< length;i++){
			var arg = argArray[i];
			var argName = arg.split("=")[0];
			var argValue = arg.split("=")[1];
			var encodedArgValue = encoder(argValue);
			url_request = url_request + "&" + argName + "=" + encodedArgValue;
		}
		
		xmlhttp_request= createXMLRequester();		
		xmlhttp_request.onreadystatechange = callbackFun;				
		//附加currentTime参数的目的是每次调用的url不一样，便于去除浏览器缓存的影响
		url_request = url_request + "&currentTime=" + new Date();
		xmlhttp_request.open('GET', url_request, true); 
		xmlhttp_request.send(null); 
	}
		
	function encoder(sourceText)
	{
		if(typeof(sourceText) == "undefined" || sourceText.length == 0){
			return null;
		}	
		if (window.RegExp && window.encodeURIComponent) {
			var encodedText=encodeURIComponent(sourceText);
			while(encodedText.indexOf("%")!=-1){
				encodedText = encodedText.replace(new RegExp("%"),":");
			}
		}
		return encodedText;
	}