MDN Playgroung
Mozilla has introduced MDN Playgroung, a platform for previewing HTML, CSS and JavaScript in the browser. Users can share code snippets and use them to show examples in documentation.
MDN Web Docs administration plans to use the platform to design code examples on the site. Now developers will be able to run code directly in the browser and see the result of its work.
Also the code can be quickly edited and see the result of its work. Play buttons will gradually appear above the code blocks in MDN, allowing you to go to Playgroung.