function $(obj_id) {
	return document.getElementById(obj_id);
}
function navigateTo(url) {
	window.location.href = url;
}
function toggleSubcat(id) {
	var t = $('subcat_' + id).style;
	t.display = (t.display == 'none' ? 'block' : 'none');
}
function openWindow(url, w, h) {
	open(url, "", 'menubar=no,directories=no,location=no,resizable=no, target=viv, scrollbars=no, width='+(w+20) +',height='+(h+20));
}