How mobile YouTube page autoplay videos on iOS?

Question

I'm trying to get it understand but after 2 days of digging the code I thought that I will post my issue here...

According to Apple's documentation, autoplaying videos on iOS devices cannot be done without user interaction first (e.g. tap on video). Despite that, mobile YouTube (m.youtube.com) is able to autoplay its videos just after loading a page with video.

Does anyone know how they are doing it?

PS. I've checked all available JS/HTML techniques of autoplaying videos on website on iOS (e.g. iframe, fake click, triggering touch event on video, fetching video with XHR).

Answer 1

I believe that youtube.com is a single page app. So when the user clicks on the video from the list view the page is not loading and their javascript uses that initial click, that leads to the video page, as the click that starts the video. It's not actually autoplaying, it's just a trick.