jQ Выпадающий список (ul) с возможностью выбора пункта. (custom)

ul-select

//Документация http://codepen.io/markhillard/pen/Pwaqdb
//--HTML--//
<div class="wrap-drop" id="noble-gases">
		<span>All Noble Gases</span>
		<ul class="drop">
			<li class="selected"><a>All Noble Gases</a></li>
			<li><a>Helium</a></li>
			<li><a>Neon</a></li>
		</ul>
</div>
//--end HTML--//

//--CSS--//
//drop-select-ul
	.wrap-drop {
		background:#fff;
		box-shadow:3px 3px 3px rgba(0,0,0,.2);
		cursor:pointer;
		margin:0 auto;
		max-width:225px;
		padding:1rem;
		position:relative;
		width:75%;
		z-index:3;
	}

	.wrap-drop::after {
		border-color:#695d52 transparent;
		border-style:solid;
		border-width:10px 10px 0;
		content:"";
		height:0;
		margin-top:-4px;
		position:absolute;
		right:1rem;
		top:50%;
		width:0;
	}

	.wrap-drop .drop {
		background:#fff;
		box-shadow:3px 3px 3px rgba(0,0,0,.2);
		display:none;
		left:0;
		list-style:none;
		margin-top:0;
		opacity:0;
		padding-left:0;
		pointer-events:none;
		position:absolute;
		right:0;
		top:100%;
		z-index:2;
	}

	.wrap-drop .drop li a {
		color:#695d52;
		display:block;
		padding:1rem;
		text-decoration:none;
	}

	.wrap-drop span {
		color:#928579;
	}

	.wrap-drop .drop li:hover a {
		background-color:#fffaec;
		color:#000;
	}

	.wrap-drop.active::after {
		border-width:0 10px 10px;
	}

	.wrap-drop.active .drop {
		display:block;
		opacity:1;
		pointer-events:auto;
	}
//--end CSS--//

//--JS--//
//drop-select-ul
function DropDown(el) {
    this.dd = el;
    this.placeholder = this.dd.children('span');
    this.opts = this.dd.find('ul.drop li');
    this.val = '';
    this.index = -1;
    this.initEvents();
}
DropDown.prototype = {
    initEvents: function () {
        var obj = this;
        obj.dd.on('click', function (e) {
            e.preventDefault();
            e.stopPropagation();
            $(this).toggleClass('active');
        });
        obj.opts.on('click', function () {
            var opt = $(this);
            obj.val = opt.text();
            obj.index = opt.index();
            obj.placeholder.text(obj.val);
            opt.siblings().removeClass('selected');
            opt.filter(':contains("' + obj.val + '")').addClass('selected');
        }).change();
    },
    getValue: function () {
        return this.val;
    },
    getIndex: function () {
        return this.index;
    }
};

$(function () {
    // create new variable for each menu
    var dd1 = new DropDown($('#noble-gases'));
    // var dd2 = new DropDown($('#other-gases'));
    $(document).click(function () {
        // close menu on document click
        $('.wrap-drop').removeClass('active');
    });
});
//--end JS--//