These notes introduce Hypertext Markup Language (HTML), the programming language we use to write webpages and Cascading Styles Sheets (CSS), the programming language we use to style those webpages. We look at the fundamental concepts of HTML, the features the language provides to us, and how we markup our content with HTML tags to create documents that web browsers can understand. We look at CSS rules and declarations and how we use them to change the presentation of our webpages.
Related reading
The Mozilla Developer Network (MDN) has some good introductory articles on HTML and CSS. MDN is a very good resource for web developers, it covers a lot of web technologies in depth and is fairly reliable; MDN should be one of the first places you look for documentation/tutorials on web technologies.