detect when a window I've opened closes - js
<p>I am building a small web app.
In the app I open a window using JS:</p>

<pre><code>signinWin = window.open("myWindow.htm", "SignIn", "width=600,height=270,location=0,toolbar=0,scrollbars=0,status=0,status=false,statusbar=false,titlebar=no,dependent,alwaysraised,resizable=0,menuBar=0,left=" + 300 + ",top=" + 300);
</code></pre>

<p>I wish to be notified via event when the user closes the window.</p>

<p>How can this be done?</p>

<p>Thank you!</p>
