gistfile1.txt

(function($) {

    $('math').length && !hasMathMLSupport() && (function() {

        // Add CSS fallback
        $('<link href="/media/css/libs/mathml.css" rel="stylesheet" type="text/css" />').appendTo(document.head);

        // Add notification
        $('#wikiArticle').prepend('<div class="notice"><p>Your browser does not support MathML.</p></div>');

    });

    // https://github.com/Modernizr/Modernizr/blob/master/feature-detects/mathml.js
    function hasMathMLSupport() {
        var $div = $('<div class="offscreen"><math><mspace height="23px" width="77px"/></math></div>').appendTo(document.body);
        var box = $div.getBoundingClientRect();
        $div.remove();
        return Math.abs(box.height - 23)  && Math.abs(box.width - 77);
    }

})(jQuery);