ajax请求

window.ajax = function(data){
	var type = data.type, url = data.url;
	 var request = false;
	 var result;
	   try {
	     request = new XMLHttpRequest();
	   } catch (trymicrosoft) {
	     try {
	       request = new ActiveXObject("Msxml2.XMLHTTP");
	     } catch (othermicrosoft) {
	       try {
	         request = new ActiveXObject("Microsoft.XMLHTTP");
	       } catch (failed) {
	         request = false;
	       }  
	     }
	   };
	   if (!request) result = "ajax Config Error!";
	    request.open(type, url, true);
	    request.onreadystatechange = callBack;
	    request.send(null);
	   function callBack(){
	        if( request.readyState == 4 && request.status == 200 ){
	             result = request.responseText;
	             alert(result);
	        }else{
	                if(request.readyState == 4){
	                        result = "Error";
	                        return false;
	                }
	        }
	   };
	   
	   return result;
}