Modernizr.addTest('fullscreen',function(){ for(var i = 0; i < Modernizr._domPrefixes.length; i++) { if( document[Modernizr._domPrefixes[i].toLowerCase() + 'CancelFullScreen']) return true; } return !!document['cancelFullScreen'] || false; }); // http://developer.apple.com/library/safari/documentation/AudioVideo/Conceptual/Using_HTML5_Audio_Video/ControllingMediaWithJavaScript/ControllingMediaWithJavaScript.html#//apple_ref/doc/uid/TP40009523-CH3-SW20 // https://developer.mozilla.org/en/API/Fullscreen