It makes websites interactive, creates animations, ... Not only will you learn JavaScript, HTML, and CSS, ... complete beginners and does expect you to have a basic grasp on HTML, CSS, and JavaScript.

Add a short CSS class to an HTML Web page to use animated and stationary GIF images as the page's background. ... GIFs can only display 256 colors, and are usually used to display clip art, ...

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.