ajax javascript get

ajax.js

function getAjax(){
	var xmlhttp;
	if (window.XMLHttpRequest)
	  {// code for IE7+, Firefox, Chrome, Opera, Safari
	  xmlhttp=new XMLHttpRequest();
	  }
	else
	  {// code for IE6, IE5
	  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
	  }
	  return xmlhttp;
}

function getUrlResponse(url, params, callback){
	var http = getAjax();
	if(params){
		url += "?";
	}
	for(param in params){
		url += param + "=" + encodeURIComponent(params[param]) + "&";
	}
	http.open("GET", url,true);
	http.send(url);
	http.onreadystatechange = function(){
		if (http.readyState == 4){
			callback(http.responseText);
		}
	}
}