var xmlHttp
function ajax()
{
	 try{xmlHttp=new XMLHttpRequest();}catch(e){try{xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");	}catch(e2)
	 {try	{xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");}catch(e3){try{xmlHttp=new ActiveXObject("Msxml2.XMLHTTP.4.0");}
	 catch(e4){xmlHttp=null;alert("xmlHttp init Error!");}}}}
}
ajax.prototype.getAjax = function(url , callBack , data)
{
	xmlHttp.onreadystatechange = callBack;
	xmlHttp.open("POST" , url);
	xmlHttp.setRequestHeader("content-length",data.length);
	xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 
	xmlHttp.send(data);
}