jsFiddle lets developers play with the three core elements of Web development. Check out this powerful application for rapid prototyping and testing.

Use this handy, simplified guide to quickly learn HTML and CSS -- a foundation of modern web development.

HTML provides the structure, content and layout, CSS adds style and design, and JavaScript adds functionality and interactivity.

In projects founded on HTML, CSS, and JavaScript, though, it’s often a pain to have to jump between contexts and always keep the thread of your tasks in mind.

HTMX is the HTML extension syntax that replaces JavaScript with simple markup. It could change the course of web development.

Learn HTML and CSS online for free, and use them to create webpages or move up in your career.