function popup(url, id, w, h) {
	var sw = 1024, sh = 768;
	if (document.all || document.layers) {
		sw = screen.availWidth;
		sh = screen.availHeight;
	}
	var lp = (sw-w)/2, tp = (sh-h)/2;

	var newWindow = window.open(url, id, 'height='+h+', width='+w+', top='+tp+', left='+lp+', toolbar=no, menubar=no, scrollbars=yes, resizable=yes, location=no, directories=no, status=no');
	if (window.focus) { newWindow.focus(); }
	return false;
}