var xmlHttp=createXmlHttpRequestObject();
var cache=new Array();

//-------------create XMLHttpRequest() or ActiveXObject()-------------
function createXmlHttpRequestObject()
{
	var xmlHttp;
	try
	{
		xmlHttp=new XMLHttpRequest();
	}
	catch(e)
	{
		var xmlHttpVersion=new Array("MSXML2.XMLHTTP.6.0",
									 "MSXML2.XMLHTTP.5.0",
									 "MSXML2.XMLHTTP.4.0",
									 "MSXML2.XMLHTTP.3.0",
									 "MSXML2.XMLHTTP",
									 "Microsort.XMLHTTP"
									 );

		for(var i=0; i<xmlHttpVersion.length &&  !xmlHttp; i++)
		{
			try
			{
				xmlHttp=new ActiveXObject(xmlHttpVersion[i]);
			}
			catch(e){}
		}

	}
	if(!xmlHttp)
	{
		alert("creating xmlHttp Object error.");
	}
	else
	{
		return xmlHttp;
	}
}

//-------------Load ajax url, post value and div id-------------
function ajax(url, div_id, postv_value){
	document.getElementById('ajax').value = div_id;
	xmlHttp.open("POST", url, true);
	xmlHttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    xmlHttp.setRequestHeader("Content-length", postv_value.length);
    xmlHttp.setRequestHeader("Connection", "close");
	xmlHttp.onreadystatechange = handleServerResponse;
	xmlHttp.send(postv_value);
}

//-------------onreadystatechange when xmlHttp.status==200-------------
function handleServerResponse()
{		
	if(xmlHttp)
	{
		if(xmlHttp.readyState==4)
		{
			if(xmlHttp.status==200)
			{
				try
				{	
					var response=xmlHttp.responseText;
					div_id = document.getElementById('ajax').value;
					document.getElementById(div_id).innerHTML=response;
					document.getElementById('ajax').value='';
				}
				catch(e)
				{
					alert("Server response data error.");
				}
			}
		}
	}
}