$(document).ready(function () {

    $('#top_menu .sub').mouseenter(function (e) {
        $($(e.target).find('.submenu')).css({
            'display': 'block'
        });
    });
    $('#top_menu .sub').mouseleave(function (e) {
        $($(e.target).find('.submenu')).css({
            'display': 'none'
        });
    });
        $('#top_menu .submenu').mouseleave(function (e) {
        $('.submenu').css({
            'display': 'block'
        });
    });

});