stop html5 video from auto playing

Hello, when I click on a video url, I know how to block flash so as to read from the video page info on that video to see if I wan't to watch it or not,
but lately some videos are html5.
Is there a way to stop html5 video from auto playing.


YouTube HTML5 Video Player[/h] This is an opt-in trial of HTML5 video on YouTube. If you are using a supported browser, you can choose to use the HTML5 player.
If you encounter any problems, right-click on the player and choose "report playback issue", or let us know on the user support forums. Your feedback will help us continue to improve the player.