<audio>
and <video>
tags without Javascript.video/webm
<video preload="auto" controls="controls" autoplay="autoplay">
<source src="https://www.elecard.com/storage/video/140626_av1_720p_850kbps.webm" type='video/webm'>
</video>
HTMLMediaElement.canPlayType('video/webm')
→ MediaSource.isTypeSupported('video/webm')
→