jsFiddle is the perfect solution; it provides a custom environment (based on user selections) to test (or fiddle with) your JavaScript, HTML, and CSS ... code in the appropriate areas of the page.

HTML code describes data and explains the overall structure of a webpage. Cascading style sheets (CSS) format the content on the page, add color, configure fonts and make webpages more readable by ...

New Vision support with GitHub Copilot in the latest Visual Studio Code Insiders build takes a user-supplied mockup image and creates a web page from it in seconds, handling all the HTML and CSS.