[Aetae]

<script>
function newWin(){
    var win = window.open("http://javascript.ru", "JSSite", "width=420, height=230, resizable=yes, scrollbars=yes, status=yes");

    (function timer(){
        if(win.closed) doSomething(win);
        else setTimeout(timer, 100);
    }())

    return win;
}
function doSomething(win) {
    return alert( win.closed );
}
</script>
<div onclick="newWin();">Open</div>