AJAX - Aumentar el tiempo de carga en ajax

<script type="text/javascript">

<!--

function getPages(divid,url)

{

 if(divid !="" && url != "")

 {

	document.getElementById(divid).innerHTML='<img src="loading_carrito.gif">';

	var ob= AjaxObject();

	var unixTimeStamp= fetch_unix_timestamp();

	var nocacheurl = url;

	ob.onreadystatechange=function()

	{

      if(ob.readyState==4)

       {

		   if(ob.status == 200)

		   {

			   if(ob.responseText != null)

			   {

				   document.getElementById(divid).innerHTML=ob.responseText;

			   }else

			     {

					 alert('There was an error: no data was received');

				 }

		   }else

		     {

			   alert('Ajax error:' + ob.statusText);

		     }

		}

    }

    ob.open("GET",nocacheurl,true);

    ob.send(null);

	}else{

    alert('Colocar el id del DIV o el URL en el href en el evento de onClick ');

	}

}

function fetch_unix_timestamp()

{

    return parseInt(new Date().getTime().toString().substring(0, 10))

}

function AjaxObject()

{

var xmlHttp;

  try{

   return xmlHttp=new XMLHttpRequest(); // Firefox, Opera 8.0+, Safari

    }

     catch (e){

     try{

      return xmlHttp=new ActiveXObject("Msxml2.XMLHTTP"); // Internet Explorer

       }

       catch (e){

       try{

        return xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");

        }

       catch (e){

     alert("Tu navegador no soporta AJAX.");

    return false;

  }

 }

}

}

//-->

</script>

$(document).ready (function(){

    window.setTimeout(function () {

        document.getElementById(divid).innerHTML=ob.responseText;

        $("#CierroAlertaCarro").alert('close');}, 4000);