If you're just doing it for fun, check out Construct2. It's a pretty cool HTML5 game engine with a lot of built in features you would normally have to code into a game yourself. Check it out and see if it's for you.
Thanks for recommending us Roy!
If anyone is interested in seeing some games that have been made in Construct 2, these are worth a look at on our arcade:
http://www.scirra.co.../super-ubi-land
http://www.scirra.co...es/848/airscape
http://www.scirra.co...ear-of-unicorns