Back in 2012, Mozilla launched Thimble, an online code editor for teaching the basics of HTML, CSS and JavaScript. Over time, though, things got pretty quiet around the project as other browser ...

Output: The results of executing the CSS, HTML, and JavaScript entered into the sections of the page. Figure A shows jsFiddle loaded in Internet Explorer 9 with empty code panes.

Thimble, which is part of Mozilla's recently launched Webmaker project, is meant to help novice users write and edit basic HTML and CSS right in a web-based code editor.

It is written in HTML, CSS, and JavaScript, which run in a thin native shell, and supports 30-odd languages. Brackets extensions are also written in JavaScript and can call Node.js modules.

Besides JavaScript, HTML, and CSS, you can edit Markdown files and see the rendered Markdown, and you can work with TypeScript. In addition, you can of course code in any .Net language, in C++ ...