Source : HowStuffWorks.com HowStuffWorks is a commercial edutainment website that was founded by Marshall Brain explaining the way many things work. The site uses photos, diagrams, videos and animations to explain complex terminology and mechanisms in easy-to-understand language.

See more here:
How Stuff Works

Source : W3Schools.com W3Schools is a web developer’s portal, with tutorials and references relating to web development subjects, including HTML, XML, CSS, JavaScript, PHP, and SQL. W3Schools is free of charge, and is funded through text and display advertising.

Read the original:
W3Schools ~ Web Developer’s Portal, with Tutorials and References