I have a Youtube clip in a hidden DIV on my page.
After the page has loaded I wanted the video to load quietly in the background so that when the user clicks the but
I think you need to also show the video. Have you ever noticed on embedded videos in webpages that they don't even show the preview static image until they scroll into view?
I think you will be fighting YouTube's algorithms on that one. its probably their goal NOT to load videos until a user clicks on them.