var myWnd = null;

function popwin(url,winw,winh) {
	if((myWnd) && (!myWnd.closed)) {
		myWnd.close();
	}
	aw = screen.availWidth - 10;
	ah = screen.availHeight - 30;
	px = (aw-winw)/2;
	py = (ah-winh)/2;
	wndProps = "top="+py+",left="+px+",width="+winw+",height="+winh+",";
	wndProps += "dependant=yes,toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=no";
	myWnd = window.open(url,"",wndProps);
	myWnd.focus();
}