需要播放下一个视频，当当前视频时间达到给定值时，但不知道为什么应该获取 currentTime 的事件根本没有触发？也许有人知道为什么（显然最简单的任务是最容易出现问题的任务）
function setupVideoPlayer() {
var currentVideo = 1;
// i.e. [video url, start time, end time]
var videos = [["1.mp4", 0, 4], ["2.mp4", 3, 7]];
var videoPlayer = document.getElementById('videoPlayer');
// set first video clip
videoPlayer.src = videos[0][0]; // 1.mp4
// Syncrhonization function should come here
videoPlayer.addEventListener('timeupdate', function(e){
if (this.currentTime == videos[currentVideo-1][2]) {
currentVideo += 1;
this.src = videos[currentVideo-1][0];
this.play();
}
}, true);
// It makes sure the seek will happen after buffering
// the video
videoPlayer.addEventListener('progress', function(e) {
// Seek to start point
this.currentTime = videos[currentVideo-1][1];
}, false)
}