Menu edge offscreen fix

$(function () {
    $(".staff-filter__menu li").on('mouseenter mouseleave', function (e) {
        if ($(this).children('ul').length) {
            var elm = $(this).children('ul');
            var off = elm.offset();
            var l = off.left;
            var w = elm.width();
            var docW = $(window).width();

            var isEntirelyVisible = (l + w + 20 <= docW);

            if (!isEntirelyVisible) {
            	var difference = (l+w) - docW + 20;
                $(this).children('ul').css("left", -difference);
            } else {
                $(this).children('ul').css("left", "0");
            }
        }
    });
});