Show warning message before close window in Java Script

Question

I've try this:

<body onunload="LogoutNoAsk();"> </body>

and the function is:

function LogoutNoAsk()
{
    alert("Please press the Logout button to logout.");
    parent.close();

}

When I press close which is the 'X' button on the top right of the window, it close straightaway without the warning message. What's wrong?

Aaron Powell · Accepted Answer

You're actually wanting to use the onbeforeunload event which allows you to block the close event.

See the MDN reference for details, but the code required would be:

window.onbeforeunload = function(e) {
    return 'Please press the Logout button to logout.';
};

Donate For Us