I'm creating a series of video tutorials and would like to prevent users from seeking forward and skipping sections. I'll be using an HTML5 video player that will be used for desktop and iPad browsers. Ideally, I'd like this to work on the iPhone as well, but I realize you have no control over the video on the phone since it uses the iPhone video player.
How can I prevent users from seeking forward on an HTML5 video player?
If you really want to do this amazingly user-hostile thing, then you can make use of the controls attribute. You will have to implement any controls you do want to allow using JS.
Of course, the user can always just view > source to get the URI of the video and download it.
I agree with @Bart Kiers that this is not a very good idea, but if you must do it, I can think of one way: hide the controls and provide your own play button that starts the video using JavaScript.