使用js检测浏览器是否支持html5中的video标签的方法

//检测是否支持HTML5
function checkVideo() {
    if (!!document.createElement('video').canPlayType) {
        var vidTest = document.createElement("video");
        oggTest = vidTest.canPlayType('video/ogg; codecs="theora, vorbis"');
        if (!oggTest) {
            h264Test = vidTest.canPlayType('video/mp4; codecs="avc1.42E01E, mp4a.40.2"');
            if (!h264Test) {
                return false;
            }
            else {
                if (h264Test == "probably") {
                    return true;
                }
                else {
                    return false;
                }
            }
        }
        else {
            if (oggTest == "probably") {
                return true;
            }
            else {
               return false;
            }
        }
    }
    else {
        return false;
    }
}