CodePen
CodePen is a social development environment for front-end designers and developers. Build and deploy a website, show off your work, build test cases to learn and debug, and find inspiration.
Code Sharing & Playground
Codeshare
Share code in real-time with developers in your browser. An online code editor for interviews, troubleshooting, teaching & more…
JSFiddle
Code Playground. Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle code editor.