Oh my God... the OP didn't ask for a "my language is bigger than yours" fight!
Javascript (also called JScript or JS for short) is a healthy complement to your HTML. It's a very handy tool that makes your web pages much more dynamic. Buttons that move images or change them with other images. Add text to a div depending on user input. A heck of a lot is available with JS.
Tutorials:
www.w3schools.com/js/default.aspwww.webteacher.com/javascript/www.echoecho.com/javascript.htmI could go on forever.
When you are interested in starting to write actual programs, for the computer, I recommend starting with a simple language, such as Visual Basic, to learn the basic concepts of programming. After you can write some fairly complicated code (manipulating files is a good checkpoint), move on to other, more widely used languages, such as C++, C#, Java, Python (for games), etc. It's really up to you. I went from VB to C++ myself.
Good luck, and feel free to write back for any help understanding any languages you try. If we know the answer, we'll help you out.