var pop = null;

function popdown() {
	if (pop && !pop.closed) pop.close();
}

function popup(obj,w,h) {
	var url = (obj.getAttribute) ? obj.getAttribute('href') : obj.href;
	if (!url) return true;
	w = (w) ? w += 20 : 525;
	h = (h) ? h += 25 : 680;
	var args = 'width='+w+',height='+h+',resizable,scrollbars';
	popdown();
	pop = window.open(url,'',args);
	return (pop) ? false : true;
}

window.onunload = popdown;
window.onfocus = popdown;