$(document).ready(function() {

	$("#main_navigation .children").css('display','none');
	$("#main_navigation ul").css({display: "none"}); // Opera Fix

	$("#main_navigation li, #main_navigation li a").hover(
	
		function(){
			$(this).find('ul:first').css({visibility: "visible",display: "none"}).show();
		},
		
		function(){ 
			$(this).find('ul:first').css({visibility: "hidden"});
	 	}
	 );
});//end jquery