window.onload=function(){
var element = $('tab');
var submenu = $('submenu');
	Event.observe(element, 'mouseover', function(event){
		$('submenu').show();
	});
	Event.observe(element, 'mouseout', function(event){
		$('submenu').hide();
	});
	Event.observe(submenu, 'mouseover', function(event){
		$('submenu').show();
	});
	Event.observe(submenu, 'mouseout', function(event){
		$('submenu').hide();
	});
}