Show warning message before close window in Java Script

Question

I\'ve try this:

and the function is:

function LogoutNoAsk()
{
    al         


        

Answer 1

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.';
};