Webm Looper Userscript
A userscript which automatically enables looping on Webm videos in your browser.
This requires you to have a userscript engine installed, one like
GreaseMonkey, Scriptish or TamperMonkey.
By default it only loops single .webm files (urls which end in .webm). Include any page you'd like and it should work on that page. Note that it loops every video, not just webm.
Test .webm file
Github does strange things to my test webm file (darkens and loading thingy, but lightens up every replay) so for now please user your own or this file for testing.