I deleted this script, because it's meaning was becoming lost on people. I added a few lines to stop autoplaying videos in the new Youtube, which wasn't really in the original description, but also it didn't prevent the video from going into your watch history, even though it stopped the autoplay and some videos played anyway and the purpose was beyond me. I decided to put it back on as is, take it or leave it. It's an unstable script with an odd purpose, and it only does half the job.
So I notice a new thing about Youtube I don't like. When I click a (profile) user link or a channel link, it takes me to a page with an autoplaying video, rather than a list of videos. I just want the list on the /videos page, so I have to click again to get to the list. Then I notice the autoplaying video from the prev page has the "watched" label even though I only saw a second of it. This stops such links to that page.
I wrote this for personal reasons. I hope it's not too strict of avoiding the page with the autoplay. This will remove all means of getting to that kind of page.
Also (I don't like), any playlist link, will go to the first video in the playlist and start playing; I want to see the list first without a video playing. This will make links go to the playlist list page first, then we can go to the autoplaying video page from there if we want.
Note: this is not anti-playlist, it's just anti autoplaying-first-video and list view from the links instead.
Version 2 - I had a complaint this didn't stop all the autoplay videos (which was added after I wrote this and also wasn't the original intent.) rather than renaming this script to not cause confusion about the new Youtube autoplay feature, I just disabled that new feature too. QUICK UPDATE 2.4 - changed the onload to an interval to stop when video found, because tricky videos weren't pausing.
Update 1.0.4 - Included Non-SSL Urls as per requested. I didn't know that Google had non https on any pages anymore.
Update 1.0.2 I could have sworn I already made it not to work on video and list pages, but argh! Fixed.
Update 1.0.1 This was driving my nuts! It wasn't working on hover card links. I freaked and deleted my script that would not work from version 1. Then I realized it's because hovercard is in an external iframe, so all I did was add another @include (thank god for undelete)
I may need to add more @includes. I don't know how many many possible URLs that hovercard comes in, but I didn't want to make it for all of apis.