JS Fiddle is a good alternative which has lots of features. The best feature for me is the collaboration tool. This allows you to invite anyone to view your work to allow them to help, assist or provide ideas for you. It can be a very interactive way of learning and experimenting. All you need to do is provide the link, share it with others and they can use this URL to see your window. If you ask a question on a forum you can give others a link to your fiddle. Audio chat is also available to allow you to communicate easily with others. Another aspect is the Tidy button, this will automatically tidy up your code which will aid in readability of you code.