What're the benefits of removing iFrames over using an adblocker like uBlock? Seems like global iFrame genocide would hurt your user experience more. They're not all ads!
This is a bookmarklet, not an extension, so you only activate it when you need it. To answer your actual question: autoplay videos that follow you when you scroll >:|
Kind of random comment, but thank you! I switched to Firefox from Chrome a few weeks ago, and one of my major annoyances was that Firefox would play Youtube videos opened in background tabs, even before the tab ever got focus. Seeing your comment gave me the idea to search about:config for a setting related to autoplay, and I found a setting that enables my preferred behavior.
I work at a bank and not on the tech side so I'm restricted to IE 11 with no addons. iFrame genocide is as close to uBlock as I can get while working. At home of course it's ghostery and uBlock.