I agree with DROO: learn Lua. It's a nice language, and it'll give you a good foundation to learn JavaScript later if you go that way, as it's sorta like a simplified version of it. Or at least a version without the terrible stuff.
Bonus (maybe): World of Warcraft addons are written in Lua.
And if you learn JavaScript, beware, there are many many sites that advocate terrible practices. Stick to
the good parts and you'll be mostly fine, though. Also JavaScript does not belong inside any HTML tag except <script>.