During the Programming Classes, I teach a lot of basics on HTML and CSS. Eventually, we’re venturing out into more advanced topics that students might want to take on at home. During that time, I’m answering a lot of questions via email but also encourage everybody to work with documentation sites like MDN (Mozilla Developer Network). Before students work with these sites, we do an introduction session on how to use it.

For CSS, there are a few key things to look for:

• Explanation (What does it do?)
• Syntax + Valid Values (How do I need to write it down?)
• Examples (How does it work?)
• Browser Compatibility (In which Browsers does it work?)

What other sites / online resources do you use to look up tech specs?