一段简易代码，当然你也可以保存在服务器，加上视频ID，等等，自由发挥吧

<div class="div">
    <video class="video000" id="myvideo" controls="controls" style="width: 6rem;height: 200px;">
        <source src="12.mp4" type="video/mp4"></source>
    </video>
</div>
<script type="text/javascript">
    var video = document.getElementsByTagName('video')[0];
    var currentTime = localStorage.getItem("currentTime");
    //console.log(currentTime);
    video.addEventListener("loadedmetadata", function() {
        this.currentTime = currentTime;
    });
    video.addEventListener("timeupdate", function() {
        var currentTime = Math.floor(video.currentTime);
        localStorage.setItem("currentTime", currentTime);
        //console.log(localStorage.getItem("currentTime"));
    });
</script>