使用方法：

1、head引入css部分

<style>
.video-con{ width: 300px; height: 150px; position: relative; margin-bottom: 20px;}
.video-con .video{ width: 100%; height: 100%;}
.video-con .btn{ width: 64px; height: 64px; background: transparent url("img/play-btn.png") no-repeat;
	position: absolute; left: 50%; top: 50%; transform: translate(-50%,-50%); border: none;
}
.video-con .btn.pause{ background-image: url("img/pause-btn.png");}
</style>

2、body引入HTML代碼

<div class="video-con">
    <video class="video"  poster="">
        <source src="mp4/1.mp4" >
    </video>
    <button type="button" class="btn js-play-btn"></button>
</div>

<!--html5的video-->
<script type="text/javascript">
    // 視頻------視頻截圖 ~~ 視頻播放狀態(tài) ~~
    const setMedia = function(video, scale = 0.8) {
        // 設(shè)置poster屬性：（非本地視頻資源會(huì)有跨域截圖問(wèn)題）
        video.addEventListener('loadeddata', function(e) {
            // 拿到圖片
            let canvas = document.createElement('canvas');
            canvas.width = video.videoWidth * scale;
            canvas.height = video.videoHeight * scale;
            canvas.getContext('2d').drawImage(video, 0, 0, canvas.width, canvas.height);
            let src = canvas.toDataURL('image/png');
            // 顯示在dom，測(cè)試用
            (function(flag = true) {
                if (!flag) {return;}
                let img = document.createElement('img');
                img.src = src;
                document.body.appendChild(img);
            })(0);
            // 設(shè)置屬性
            video.setAttribute('poster', src);
        });
// -------------------------------------------------------------------------------------
        //檢測(cè)視頻播放狀態(tài)：
        //播放按鈕
        let playBtn =  video.parentNode.childNodes[2].nextSibling;
        //設(shè)置狀態(tài)
        function vidplaySate(e) {
            if (video.paused) {
                video.play();
                playBtn.classList.add('pause');
            } else {
                video.pause();
                playBtn.classList.remove('pause');
            }
        }
        //點(diǎn)擊監(jiān)聽(tīng)
        video.addEventListener('click', vidplaySate, false);
        playBtn.addEventListener('click', vidplaySate, false);
        //結(jié)束監(jiān)聽(tīng)
        video.addEventListener('ended',function () {
            playBtn.classList.remove('pause');
        });
    };
    //視頻：
    let videos = document.querySelectorAll('video');
    videos.forEach((video) => {
        setMedia(video);
    });

</script>