HyperText Markup Language (HTML) is the main markup language for displaying web pages and other information that can be displayed in a web browser. Learning to create pages and sites is like weaving your own threads through a world full of content called the Internet, or Net.
HTML is written in the form of HTML elements consisting of tags enclosed in angle brackets (like <html>), within the web page content. HTML tags most commonly come in pairs like <h1> and </h1>, although some tags, known as empty elements, are unpaired, for example <img>. The first tag in a pair is the start tag, the second tag is the end tag (they are also called opening tags and closing tags). In between these tags web designers can add text, tags, comments and other types of text-based content. Our publications will hopefully help you uncover all you want to know about web elements. The first 8 in the series helps you learn basic HTML.
The purpose of a web browser is to read HTML documents and compose them into visible or audible web pages. The browser does not display the HTML tags, but uses the tags to interpret the content of the page. Your creativity comes to life on the page.
Web browsers can also refer to Cascading Style Sheets (CSS) to define the appearance and layout of text and other material. The W3C, maintainer of both the HTML and the CSS standards, encourages the use of CSS over explicitly presentational HTML markup. We will try to cover topics to help you build as much as you want with as much information as you need.
Using CSS requires basic experience with HTML. If you are not familiar with HTML, please start with our Basic HTML tutorial before moving on to CSS.
Some information obtained from: http://en.wikipedia.org/wiki/HTML