How to load Font Awesome asynchronously

    <script type="text/javascript">
    (function() {
        var css = document.createElement('link');
        css.href = '//netdna.bootstrapcdn.com/font-awesome/4.0.3/css/font-awesome.min.css';
        css.rel = 'stylesheet';
        css.type = 'text/css';
        document.getElementsByTagName('head')[0].appendChild(css);
    })();
</script>

_https://gist.github.com/saidqb/f233b58163d75c78b5d33ce899dac3e0