Fire a function only on browser close

Question

The idea is to show a customized popup / div when user closes the browser. Found this code online and it works for me partially.

JS:

window.onbeforeunload = function (e) {            
            e = e || window.event;
            if (e) {
                e.returnValue = '';
                $("#popup").show();
            }            
        }

HTML:

<div id="popup" class="popup">
</div>

When user closes the browser, an alert pops up with a confirmation, to leave or stay. Is it possible to show the popup/div without showing the default JS alert.

This piece of code also fires when user refreshes the page. How to allow this only on close event.

Answer 1

Only works in the more recent browsers to ignore the alert with a return if you don't use jquery:

window.onbeforeunload = function (e) {            
     e = e || window.event;
     if (e) {
         $("#popup").show();
     }

    return null;        

}

Events (e), actually never should be edited