ASP.Net: Force redirect when session expires

ForceRedirectOnSessionExpire.cs

//source: http://www.codeproject.com/Articles/27073/How-to-Redirect-to-Another-Page-when-Session-Timeo
//Distributed under Codeplex Project Open License: http://www.codeproject.com/info/cpol10.aspx


private void CheckSessionTimeout()
{
    string msgSession = "Warning: Within next 3 minutes, if you do not do anything, "+
               " our system will redirect to the login page. Please save changed data.";
    //time to remind, 3 minutes before session ends
    int int_MilliSecondsTimeReminder = (this.Session.Timeout * 60000) - 3 * 60000; 
    //time to redirect, 5 milliseconds before session ends
    int int_MilliSecondsTimeOut = (this.Session.Timeout * 60000) - 5; 

    string str_Script = @"
            var myTimeReminder, myTimeOut; 
            clearTimeout(myTimeReminder); 
            clearTimeout(myTimeOut); " +
            "var sessionTimeReminder = " + 
		int_MilliSecondsTimeReminder.ToString() + "; " +
            "var sessionTimeout = " + int_MilliSecondsTimeOut.ToString() + ";" +
            "function doReminder(){ alert('" + msgSession + "'); }" +
            "function doRedirect(){ window.location.href="/KB/session/login.aspx"; }" + @"
            myTimeReminder=setTimeout('doReminder()', sessionTimeReminder); 
            myTimeOut=setTimeout('doRedirect()', sessionTimeout); ";

     ScriptManager.RegisterClientScriptBlock(this.Page, this.GetType(), 
           "CheckSessionOut", str_Script, true);
}

private void Page_Load(object sender, System.EventArgs e)
{
    this.CheckSessionTimeout();
}

//To force page refresh instead of redirect replace doRedirect function with following
// function doRedirect(){ window.location.href=window.location.href; }

//If not using ScriptManager, replace with
//Page.RegisterClientScriptBlock(...)