Javascript alert() in a pop up window

Question

I have an anchor tag whose click event calls a JavaScript function, which opens a pop up window.

Now when the user clicks the close button of the pop up window I want to generate an alert() , which asks whether the user wants to close the pop up window or not

Using the below code the alert is generate in the parent window rather than the pop up

<script>
function  openForm()
{
    var new_window = window.open('file:///C:/Users/Tejora/Desktop/test.html','popup''width=825,height=585,scrollbars=yes,resizable=yes,toolbar=no,directories=no,location=no,menubar=no,status=no,left=50,top=0');
    new_window.onbeforeunload = function(){ 
           alert("Are you sure you want to close the window");      }
}
</script>


 <a href="#" onclick="openForm()">Click</a>

Thanks in advance...

Answer 1

When a string is returned from the onbeforeunload handler, the browser will display a confirmation dialog with that message. Replace this line:

alert("Are you sure you want to close the window");

With this:

return "Are you sure you want to close the window?";

Here is the relevant documentation.