W3Schools

 
 
 
W3Schools is an educational website for learning web technologies online. Content includes tutorials and references relating to HTML, CSS, JavaScript, JSON, PHP, Python, AngularJS, SQL, Bootstrap, Node.js, jQuery, XQuery, AJAX,XML,and recently they included Java also.

Created in 1998, its name is derived from the World Wide Web, but is not affiliated with the W3C (World Wide Web Consortium). It is run by Refsnes Data in Norway. W3Schools presents thousands of code examples. By using the TryIt editor, readers can edit examples and execute the code in a sandbox.
— https://en.wikipedia.org/wiki/W3Schools

W3Schools.com is full of useful resources, including:

  • Browser Statistics – Featuring W3Schools' Famous Month-by-Month Browser Statistics Since 2002 Also includes the most popular operating system platforms, screen resolutions, mobile devices, plus break-outs for Chrome, Firefox, Internet Explorer, Safari, and Opera browsers.

  • HTML Color Picker – Pick a color or enter a code to see the color. Also includes many other color related tutorials. Many have associated tools.

  • Color Converter – Enter a color or code to translate it into other schemes. Includes: color name, hex, rgb, hsl, hwb, cmyk & ncol schemes.

  • W3Schools Online Web Tutorials featuring tutorials on HTML, CSS, JavaScript, Server Side, Web Building, XML, SQL, PHP, jQuery, Python, Bootstrap & W3.CSS.