How to display alert message while closing the browser close button ?


We can display the alert message using java script while closing the close button of browser like this

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

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">

<html xmlns="">
<head runat="server">
    <script type="text/javascript">
        function confirmClose() {
            if (window.event.clientY < 0) {
                event.returnValue = "Are you sure do you want to navigate away from this page";
               // alert("are you sure ?");

<body onBeforeUnload="confirmClose()"> 
    <form id="form1" runat="server">


10 thoughts on “How to display alert message while closing the browser close button ?

  1. gowthaman March 8, 2013 / 5:06 am

    i need source code for sending sms using .. pls send source code to my mail id below

    • Chandra Dev March 8, 2013 / 10:34 am


      There is no specific code for sending sms. It is like api code which will provide by service provider. That will change depending on service provider. For this service, they will charge some money to you.

  2. Smithe52 April 20, 2014 / 11:19 pm

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    • Chandra Dev May 1, 2014 / 4:35 am

      Thanks. I am glad to know about this. I will keep on posting helpful information.

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