Well, I see that you are trying to simply have a button that will make the page full-screen; similar to the youtube full screen mode.
As well, I do NOT suggest using the "just hit F11" method, as people on Safari, or Mac in general, will be excluded.
You can use C#, which can be done by downloading Visual Studio or MS Visulal C#, or even CosmosBoot. There is plenty of code for full screen applications in C#. Another good thing about full screen in C# is that it can be easily embedded into a webpage, through some simplye ASP code.
You can use java, which can be painfully slow, and require a lot of coding, but it is attainable. You can use one of several hundred IDEs or JDKs, but I don't really use java, so I can't give you much in the way of advice on programming it, but it is EVEN EASIER to embed than C#, all you need is the <applet> tag.