Web Design in a Nutshell, 3rd Edition

Markup Basics

An HTML or XHTML document is an ASCII (plain text), or more often, Unicode (e.g., UTF-8) document that has been marked up with tags that indicate elements and other necessary declarations (such as the markup language it is written in). An element is a structural component (such as a paragraph) or a desired behavior (such as a line break). This section introduces the key components and behaviors of HTML documents, including elements, attributes, how elements may be nested, and information in a document that is ignored by browsers.