<audio>
and <video>
tags without Javascript.video/mp4
<video preload="auto" controls="controls" autoplay="autoplay">
<source src="https://www.cinemartin.com/cinec/_Sample_Videos/Hoid/Cinemartin_A001_C001_1008BA_2_H265_HEVC_RQ.mp4" type='video/mp4'>
</video>
HTMLMediaElement.canPlayType('video/mp4')
→ MediaSource.isTypeSupported('video/mp4')
→