Ok, I found this site before Xatrix, the site is http://www.hackthissite.org. Once you sign-up, you can attempt different challenges on the site, they range in difficulties. I really suggest trying it out.
My username is: lollolord123 on HTS, so give the challenges ago, I have finished all of the basic, javascript and extbasic challeneges I think, (check my profile to double check ) If you need help with any of the ones that I've finished, I'll help you out...