<source>
A media resource candidate inside picture, audio, or video.
Baseline: Widely available · Media & embedded content
When to use it
One per format or condition, ordered best-first; the browser takes the first it supports.
When not to
Only valid inside picture, audio, or video; it renders nothing on its own.
Key attributes
srcset / src- the resource
type- MIME type
media- condition (picture only)
Example
<video controls width='320' height='180'>
<source src='/media/intro.webm' type='video/webm'>
<source src='/media/intro.mp4' type='video/mp4'>
</video>