Autoplay hidden music on blogs

put this css

.blog a[href$="?autoplay=1"] {display: none;}
.blog iframe[src$="?autoplay=1"] {display: none;}

then put a youtube video link with ?autoplay=1 added on to your blog anywhere
example (without https): www.youtube.com/watch?v=om_qPG9CNig?autoplay=1

If you want to keep a video with autoplay without it being hidden just add &feature=youtu.be to the end of the link
example (without https): www.youtube.com/watch?v=m7tOm7s3iMQ?autoplay=1&feature=youtu.be

Warnign : this will cause lag loading the page
only works when browser autoplay is allowed , of course
and finally you can change the .blog to .blogs to make it work for blog comments too,but watch out for other people posting autoplay videos as well
I had thought that ads would cause a problem but for some reason it seems to not play any this way https://www.youtube.com/watch?v=om_qPG9CNig?autoplay=1