w3School

W3Schools is a popular web site for learning web technologies online.[2] Content includes tutorials and references relating to HTML, CSS, JavaScript, PHP, AngularJS, SQL, Bootstrap, Node.js, and jQuery. It receives more than 10 million unique visitors monthly.[1]

Created in 1998, its name is derived from the World Wide Web, but is not affiliated with the W3C (World Wide Web Consortium).[3] It is run by Refsnes Data in Norway.[1] W3Schools presents thousands of code examples. By using an online editor, readers can edit examples and execute the code in a sandbox.

Controversy:
Because W3Schools looks similar to W3C (World Wide Web Consortium), this has lead many to believe that W3Schools is associated with W3C. W3Schools for many years contained misleading or out of date standards and examples.[4][5] This lead many aspiring web developers to erroneously implement bad practices and development styles while thinking they were following the correct W3C standard for many years.