Cancel async function javascript

When using XMLHttprequest or other async functions in JavaScript, we may want to cancel them at times. Asynchronous tasks can be aborted in a variety of ways in JavaScript. We’ll look at how to use the ASP.NET ajax toolkit object to abort XMLHttprequest requests and other async tasks throughout this post.

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="AjaxCancel.aspx.cs"  
Inherits="AjaxCancel" %>  

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"  
<html xmlns="">  
<head runat="server">  
<title>Untitled Page</title>  
<form id="form1" runat="server">  
  <asp:ScriptManager ID="S1" runat="server">  
      <asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">  
              <%= System.DateTime.Now.ToLongTimeString() %>  
              <asp:Button ID="btnRefresh" runat="server" Text="Update"  
OnClick="btnRefresh_Click" />  

<script type="text/javascript">  
var prm = null;  

function Init(sender)  
prm = Sys.WebForms.PageRequestManager.getInstance();  
//Ensure EnablePartialRendering isn't false which will prevent  
//accessing an instance of the PageRequestManager  
if (prm)  
    if (!prm.get_isInAsyncPostBack())  
function InitRequest(sender,args)  

if (prm.get_isInAsyncPostBack() & args.get_postBackElement().id == 'btnRefresh') {  
   //Could abort current request by using:  prm.abortPostBack();   
   //Cancel most recent request so that previous request will complete   
   //and display  
   alert("A request is currently being processed.  Please " +  
         "wait before refreshing again.");  

using System;  
using System.Data;  
using System.Configuration;  
using System.Collections;  
using System.Web;  
using System.Web.Security;  
using System.Web.UI;  
using System.Web.UI.WebControls;  
using System.Web.UI.WebControls.WebParts;  
using System.Web.UI.HtmlControls;  

public partial class AjaxCancel : System.Web.UI.Page  
protected void Page_Load(object sender, EventArgs e)  

protected void btnRefresh_Click(object sender, EventArgs e)  
Next Post Previous Post
No Comment
Add Comment
comment url