function pop(url, w, h) {
	w = w ? w : '600';
	h = h ? h : '400';
	cw = w/2;
	ch = h/2;
	
	if (window.screen) {
		cw = Math.floor((screen.availWidth-w)/2);
		ch = Math.floor((screen.availHeight-h)/2);
	}
	
	window.open(url,'pop','toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=0,width='+w+',height='+h+',top='+ch+',left='+cw+',resizable=0');
}

function toggle_checkboxes(f, name) {
	var e = f.elements;
	for (i = 0; i < e.length; i++) {
		if (e[i].type == 'checkbox') {
			if (e[i].name.indexOf(name) == 0) {
				if (e[i].checked)
					e[i].checked = false;
				else
					e[i].checked = true;
			}
		}
	}
}