After several hours of exploration, I found that this is a problem with WeChat’s built-in browser itself.

Q: I also have questions. I'm working on an HTML5 page, which uses the video tag to play a video, but this video is always displayed at the top level. No matter how I adjust the z-index attribute, it doesn't work. I hope to display some text or pictures on the video. However, this problem behaves normally on PC, Apple ios, or other browsers. The only problem is the QQ browser or WeChat built-in browser under the Android system. Please give me some guidance.
A: X5 core video playback uses a self-developed player. Considering user experience, we use a unified playback interface. If you have related questions, please contact Tencent Browsing Service Product Manager for further communication

Quoted from http://x5.tencent.com/guide?id=2009

The solution is to pause the video playback when scrolling starts

var video = document.getElementsByTagName("video")[0];
      myScroll.on('scrollStart', function() {
        video.pause(); //暂停播放
        video.style.display = "none"; //隐藏
      });

Show video after scrolling:

myScroll.on('scrollEnd', function() {
        if(this.y > -_wh/2 && this.y < 0) {
            myScroll.scrollTo(0,0,500);
          }
          if(this.y > -_wh && this.y < -_wh/2) {
            myScroll.scrollTo(0,-_wh,500);
          }
            video.style.display = "block"; // 重新展示视频
      });

Online demo

WeChat Browser does not use Android’s built-in browser, but its own X5 kernel. And this X5 has extremely poor support for various web standards.

Yes, I finally removed or hide it when exiting the interface

This is a bug in mobile Android browsers, and it also exists in UC. The video level is max

Haha, I encountered this problem some time ago. My solution is to set video 0px directly after any operation

Youku, iQiyi, etc. are in the whitelist of major rogue browsers. The video will not be hijacked. If it is hijacked, it will be sued until it goes bankrupt. We and other little people can only be hijacked and fooled a a