html5 – 点击HTML 5视频元素播放,暂停视频,中断播放按钮

<video width="600" height="409" id="videoPlayer" controls="controls">
 <!-- MP4 Video -->
 <source src="video.mp4" type="video/mp4">
</video>


<script>
    var videoPlayer = document.getElementById('videoPlayer');

    // Auto play,half volume.
    videoPlayer.play()
    videoPlayer.volume = 0.5;

    // Play / pause.
    videoPlayer.addEventListener('click',function () {
        if (videoPlayer.paused == falsE) {
            videoPlayer.pause();
            videoPlayer.firstChild.nodeValue = 'Play';
        } else {
            videoPlayer.play();
            videoPlayer.firstChild.nodeValue = 'Pause';
        }
    });
</script>

你有什么想法为什么会打破播放和暂停控制按钮？