To fix the Youtube iframe loop not working with HTML, we add the playlist
query parameter.
For instance, we write
<iframe
class="embed-responsive-item"
id="ytplayer"
type="text/html"
width="640"
height="360"
src="https://www.youtube.com/embed/M7lc1UVf-VE?&autoplay=1&loop=1&rel=0&showinfo=0&color=white&iv_load_policy=3&playlist=M7lc1UVf-VE"
frameborder="0"
allowfullscreen
></iframe>
to add the playlist
parameter to the embed video URL to autoplay the playlist loop.