Hello friends. if you are a keen learner and want to learn or understand any programming language . then no other site is better than w3schools.com.
you will get every thing regarding your field of interest.topic wise topic clearly defined everything with examples with them which you can also execute there to check outputs. I am a programmer and I am using it from last 2 year. any topic which I dont understand. I can easily surf to this website and read those topics. it has also many exercises attached to every topic at the end of the every page. you can also solve these exercise to get much better knowledge and judge yourself.it has some certifiation program also where you can get certificates of w3schools. lots of Mcq questions are there.every thing which you need to learn any programming language is available at w3schools.com.