<video id="byl_video"
 style="object-fit:fill" 
 preload="auto"
 playsinline="true"
 webkit-playsinline="true"
 x-webkit-airplay="allow"
 airplay="allow"
 x5-video-player-type="h5"
 x5-video-player-fullscreen="true"
 x5-video-orientation="portrait"
 src="视频地址"></video>
var video = document.getElementById('byl_video');
document.addEventListener("WeixinJSBridgeReady", function() {
  video.play();
}, false);

video.play();