aliplay获取播放时长

            <div id="player-con" class="frequency-pic"></div>
            <link rel="stylesheet" href="https://g.alicdn.com/de/prismplayer/2.8.2/skins/default/aliplayer-min.css" />
            <script charset="utf-8" src="https://g.alicdn.com/de/prismplayer/2.8.2/aliplayer-min.js"></script>
            <script>
                var aliplayer = new Aliplayer({
                    "id": "player-con",
                    "source": '<% =videoUrl %>',
                    "width": "640px",
                    "height": "480px",
                    "autoplay": true,
                    "isLive": false,
                    "cover": '@(Course.Cover==null? "http://image.bnuxq.net/20190525/guo-pic.jpg":Course.CoverPath_pre+""+Course.Cover)',
                    "rePlay": true,
                    "playsinline": true,
                    "preload": true,
                    "language": "zh-cn",
                    "controlBarVisibility": "hover",
                    "useH5Prism": true
                }, function (player) {
                    console.log("播放器创建了。");
                }
                );

                aliplayer.autoplay = true;

                    var whereYouAt = parseFloat(aliplayer.getCurrentTime()) + ;
                    var totalTime = parseFloat(aliplayer.getDuration());