$(function mainmenu(){
	$(" #menuPrincipal .navegacion ul ").css({display: "none"}); // Opera Fix
	$(" #menuPrincipal .navegacion li").hover(function(){
		$(this).find('ul:first').css({visibility: "visible",display: "none"}).slideDown(100,"easeinout");
	},function(){
		$(this).find('ul:first').css({visibility: "hidden"});
	});
});