ajax big process causes all other processes to delay for 2 min,

Tried it on opera, chrome, firefox and Ie 9

Got the code now,
//Call back page WebForm1.aspx
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace IndyIIOrga.UserControls
{
public partial class WebForm1 : System.Web.UI.Page
{
public string sessionUserCID { get { if ( Session[ "UserCID" ] != null ) { return Session[ "UserCID" ].ToString() ?? "-1"; } else { return "-1"; } } set { Session[ "UserCID" ] = value; } }

protected void Page_Load( object sender, EventArgs e )
{
Random r = new Random();
//lblTesting.Text = string.Format( "{0}", cookieUserCID.ToString() );
lblTesting.Text = string.Format( "Indy is processing excel Line number {0}", sessionUserCID );
}

}
}

//Java that call the call back page
function SessionGetCookie()
{
$.ajax(
{
url: "../../UserControls/WebForm1.aspx",
type: 'post',
dataType: 'text',
cache: false,
success: function (data, textStatus, xhr)
{
$.cookie('UserCID', $( data ).text() );
}

});
}

//Code that loops to update the label
var sessionTimeoutWarning = 1; //1 minute
var sessionTimeout = 18;
var sTimeout = parseInt(sessionTimeoutWarning) * 10 * 1000; //Regular time is meant *60*100
setTimeout('SessionWarning()', sTimeout); //Java timer function

function SessionWarning()
{
SessionGetCookie();
$("#lblPosition9162wa").text( $.cookie('UserCID') );
setTimeout('SessionWarning()', sTimeout);

}

//Label on client machine
<asp:Label ID="lblPosition9162wa" ClientIDMode="Static" runat="server" Text="9999" >

No, they all successfully pass but are delayed when the big process starts (the excel import)
Edit. reply to previous q.
And they all fail? You'll want to post your code then.