JSFiddle is great for me to try and do quick bits of code. I don't know how to code properly so i just chuck in things from tutorials or CSShat
For example, here's a button i made with a dog gif when you click on it
http://jsfiddle.net/morz/ZKaLz/
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One of my friends told me about JSFiddle few months back; a great tool. This is particularly useful for beginners or who do not need to use HTML/CSS/JS frequently at work.
Ballpark