关于javascript:JS-video-获取视频第一帧

<div class="websocket">    <!--  poster="http://9haoguoji.oss-cn-beijing.aliyuncs.com/product/1619083692180048808.jpg" 设置 封面图 -->    <video id="video1" style="background: #ccc" width="100%" controls="controls">        <source src="123.mp4"  type="video/mp4">    </video></div>

<script type="text/javascript">    getVideoBase64('123.mp4')    function getVideoBase64(url) {       /* return new Promise(function(resolve, reject) {*/            let dataURL = '';            let video = document.createElement("video");            video.setAttribute('crossOrigin', 'anonymous'); //解决跨域            video.setAttribute('src', url);            video.setAttribute('width', 400);            video.setAttribute('height', 240);            video.addEventListener('loadeddata', function() {                let canvas = document.createElement("canvas"),                    width = video.width, //canvas的尺寸和图片一样                    height = video.height;                canvas.width = width;                canvas.height = height;                canvas.getContext("2d").drawImage(video, 0, 0, width, height); //绘制canvas                dataURL = canvas.toDataURL('image/jpeg'); //转换为base64                $('#video1 source').attr('src', dataURL)                //resolve(dataURL);            });        /*})*/    }</script>

本地能够 线上会有跨域问题 如果用的阿里服务器 后盾勾销跨域