Event.observe(window, 'load', function() {
	$$('.tab').each(function(elem) {
		elem.observe('mouseover', function() {
			elem.select('.tab_sub')[0].show();
		});
	});
	$$('.tab').each(function(elem) {
		elem.observe('mouseout', function() {
			elem.select('.tab_sub')[0].hide();
		});
	});
});