Modernizr.addTest('autoplay', function(){

    // Audio file data URIs from comments in
    // [this gist](https://gist.github.com/westonruter/253174)
    // via [mudcube](https://github.com/mudcube)
    var mp3 = 'data:audio/mpeg;base64,/+MYxAAAAANIAUAAAASEEB/jwOFM/0MM/90b/+RhST//w4NFwOjf///PZu////9lns5GFDv//l9GlUIEEIAAAgIg8Ir/JGq3/+MYxDsLIj5QMYcoAP0dv9HIjUcH//yYSg+CIbkGP//8w0bLVjUP///3Z0x5QCAv/yLjwtGKTEFNRTMuOTeqqqqqqqqqqqqq/+MYxEkNmdJkUYc4AKqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq';
    var ogg = 'data:audio/ogg;base64,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';

    try {
        var audio = new Audio();
        var src = audio.canPlayType('audio/ogg') ? ogg : mp3;
        audio.autoplay = true;
        audio.volume = 0;

        // this will only be triggered if autoplay works
        audio.addEventListener('play', function() {
            Modernizr.autoplay = true;
          // is there a better way to re-evaluate the html classes added by Modernizr?
          var root = document.getElementsByTagName('html')[0];
          root.classList.remove('no-autoplay');
          root.classList.add('autoplay');
          
          // or if you're using jQuery:
          // $('html').toggleClass('no-autoplay autoplay');
        }, false);

        audio.src = src;
    } catch(e) {
        console.log('[AUTOPLAY-ERROR]', e);
    }

    return false;
});
	

.support { line-height:50px; font-size:30px; color:white; }
.nope { background:red; }
.yep { background:green; }

.autoplay .nope { display:none; }
.no-autoplay .yep { display:none; } 

Autoplay is supported
Autoplay is not supported