JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script src="http://cdnjs.cloudflare.com/ajax/libs/modernizr/2.6.2/modernizr.min.js"></script>
<script src="https://raw.github.com/barisaydinoglu/Detectizr/master/detectizr.min.js"></script>


<h1>jQuery + Modernizr: AccessKey detection</h1>
<ul>
    <li><a href="javascript:alert('Hello')" accesskey="1">Hello</a></li>
    <li><a href="javascript:alert('World')" accesskey="2">World</a></li>
    <li><input type="text" accesskey="3" placeholder="Input text" /></li>
</ul>

CSS

*[accesskey]:after {
    margin-left: 0.3em;
    color: #ccc;
    content: "[Alt + " attr(accesskey) "]";
}

body.firefox *[accesskey]:after { content: "[Alt + Shift + " attr(accesskey) "]"; }
body.firefox.mac *[accesskey]:after { content: "[Ctrl + Opt + " attr(accesskey) "]";  }
body.safari.mac *[accesskey]:after { content: "[Ctrl + " attr(accesskey) "]";  }



h1 {
    color: #333;
    font: bold 23px Arial, sans-serif;
}

ul li a {
    color: #666;
    font: bold 13px Arial, sans-serif;
    text-decoration: none;
}

JavaScript

/**
 * Add browser and OS name to body class, and append the shortcut to element title
 * @author rogeriolino
 */
(function($) {
    $(document).ready(function() {
        Modernizr.Detectizr.detect({detectScreen:false});
        var body = $('body')
        body.addClass(Modernizr.Detectizr.device.browser + ' ' + Modernizr.Detectizr.device.os);
        $('*[accesskey]').each(function(i, e) {
            var elem = $(e);
            prefix = 'Alt';
            if (body.hasClass('firefox')) {
                if (body.hasClass('mac')) {
                    prefix = 'Ctrl + Opt';
                } else {
                    prefix = 'Alt + Shift';
                }
            } else if (body.hasClass('safari mac')) {
                prefix = 'Ctrl';
            }
            elem.prop('title', elem.prop('title') + ' [' + prefix + ' + ' + elem.attr('accesskey') + ']');
        });

    });
})($);