Glyphicon Issue

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jQuery.mmenu/5.5.3/core/js/jquery.mmenu.min.all.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/jQuery.mmenu/5.5.3/core/css/jquery.mmenu.all.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<header>
    <!-- Mobile Navigation -->
    <a href="#mobile-nav" id="menu-button">Button</a>
    <nav id="mobile-nav">
        <ul>
            <li>
                <form name="catsearchform37692" method="post" action="/search">
                    <div class="search-box">
                        <input class="cat_textbox_small" name="CAT_Search" id="CAT_Search" type="text">
                        <input class="cat_button" value="Search" type="submit">
                    </div>
                </form>
            </li>
            <li><a href="/account">My Account</a>

                <ul class="Vertical">
                    <li><a href="/account/wishlist">My Wishlist</a>

                    </li>
                    <li><a href="/account/orders">My Orders</a>

                    </li>
                    <li class="divider"></li>
                    <li>{module_logout}</li>
                </ul>
                <li><a href="/account/sign-up">Register</a>

                </li>
                <li class="Divider"></li>
                <li><a href="/account/sign-in">Log In</a>

                </li>
            </li>
            <li><a href="/">Home</a>

                <ul class="Vertical">
                    <li><a href="/about-us">About Us</a>

                    </li>
                    <li><a href="/delivery-information">Delivery Information</a>

                    </li>
                    <li><a href="/customer-services">Customer Services</a>

                    </li>
                    <li><a href="/returns-information">Returns Information</a>

                    </li>
                    <li><a href="/faqs">FAQs</a>

        ...

JavaScript

$('#mobile-nav').mmenu({
	slidingSubmenus: true
        // title: "Looking"
});

var API = $('#mobile-nav').data('mmenu');

$('#menu-button').click(function () {
    API.open();
});