1. HTMLPen is a free online Visual HTML Editor (WYSIWYG Editor) program allows you visually edit, preview, and run your html code. It is also a powerful online text editor.

  2. Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle code editor.

  3. dabblet is an interactive playground for quickly testing snippets of CSS and HTML code.

  4. Liveweave is a HTML5, CSS3 & JavaScript playground for web designers and developers

  5. Plunker is an online community for creating, collaborating on and sharing your web development ideas.