小编Bla*_*air的帖子

我正在尝试跟踪 HTML 视频中的视频播放进度。我需要跟踪 0、25、50、75 和 100%。我不确定我做错了什么，无法让 console.logs 工作。js小提琴

我得到错误

未捕获的类型错误：无法读取 null 的属性“on”

请提供任何帮助/建议

var myPlayer = document.querySelector('video');
var percentageCompleted = 0;
var totalLength = 0;
var videoStarted, videoTwentyFive, videoFifty, videoSeventyFive, videoComplete = false;

myPlayer.on('timeupdate', getPercentage);

function getPercentage() {

    percentageCompleted = (myPlayer.currentTime() / totalLength) * 100;
    //console.log('percentage', (percentageCompleted+'%'));

    // is 0
    if ((!videoStarted) && (percentageCompleted > 0)) {
        console.log('VIDEO_STARTED');
        videoStarted = true;

        window.dataLayer = window.dataLayer || [];
        window.dataLayer.push({
            'event': 'playStart'
        });
    }
    // is 25
    if ((!videoTwentyFive) && (percentageCompleted > …