How do I learn to code in HTML and CSS on my Mac? Web design is one of the most useful skills you can learn, and it’s easy to learn HTML and CSS (the two main pillars of web pages) in Mac OS X.

HTML and CSS form the basic coding languages for web design and development. If you need to perform any kind of activity related to web manipulation, a working knowledge of these two is essential.

I'm working on a web app with some dynamic forms, that show certain fields based on different form selection choices ... example on one of my forms of some HTML that would be hidden.