Question

For example I’m on domain1:

a.click(function(){
  window.win=window.open(domain2,'name');
});

Now I’m on domain2 and I’m closing it. How will window.win know that user closed that window? Is there any event or property to check via interval?

Answer 1

There is a property which is not part of any W3C spec. It’s called closed and would get accessed like

if( window.win.closed ) {
    // window was closed
}

I’m not sure about the cross-browser compatibilty for that property. I’m also not sure how this behaves on cross-origin domains. But if you try it please let me and the rest of this community know about it.

---

Another option is that you take care for the notification yourself. That means, you are listening for the onbeforeunload within the popup-window. When the event fires, you could use HTML5’s postMessage method to communicate between cross-domain windows. For instance:

MainWindow:

window.addEventListener('message', function(e) {
    if( e.origin === 'http://www.popupdomain.com' ) {
        if( e.data === 'closed' ) {
            alert('popup window was closed');
        }
    }
}, false);

Domain2:

window.onbeforeunload = function() {
    window.opener.postMessage('closed', 'http://www.popupdomain.com');
};

The only caveat on this solution is that it’s only compatible with browser that support basic HTML5. There are other (sneaky) ways to have a cross-domain communication on old’ish browsers, but I guess that is another story.