problem with a popup window

[Joseph]

I don't understand why the code below gives me an error, it says ' member not found ' as if ' win ' did not exist?
Any idea?

var win;
function popwin(strURL)
{
//alert(strURL);
win = window.open(strURL,'_self','width=520,height=410,left=0,top=0,modal=yes,dialog=yes, location=1, toolbar=0, directories=0,
status=1, menubar=1, scrollbars=1, resizable=1');
if (!win.closed) { // Its open
win.focus(); // For some reason this line causes an error: member not found
}
}

TIA
Joseph

philippeoget at hotmail dot com
http://www.geocities.com/philippeoget/a2z/