function init_dropdown_menu(el) {
	var sube = $(el).getElementsByTagName('ul')[0];
	Event.observe($(el), 'mouseover', function(e) {
		$(sube).show();
	});
	Event.observe($(el), 'mouseout', function(e) {
		$(sube).hide();
	});
}


var preloaded_images = $A();
function preload_image(url) {
	if(document.images) {
		var i = new Image();
		i.src = url;
		preloaded_images.push(i);
	}
}