What is HTML?
HTML is a markup language for describing web documents (web pages).
- HTML stands for Hyper Text Markup Language
- A markup language is a set of markup tags
- HTML documents are described by HTML tags
- Each HTML tag describes different document content
A Small HTML Document
<h1>My First Heading</h1>
<p>My first paragraph.</p>
- The <!DOCTYPE html> declaration defines this document to be HTML5
- The text between <html> and </html> describes an HTML document
- The text between <head> and </head> provides information about the document
- The text between <title> and </title> provides a title for the document
- The text between <body> and </body> describes the visible page content
- The text between <h1> and </h1> describes a heading
- The text between <p> and </p> describes a paragraph
Using this description, a web browser will display a document with a heading and a paragraph.
HTML tags are keywords (tag names) surrounded by angle brackets:
- HTML tags normally come in pairs like <p> and </p>
- The first tag in a pair is the start tag, the second tag is the end tag
- The end tag is written like the start tag, but with a forward slash inserted before the tag name
The start tag is also called the opening tag, and the end tag the closing tag.
The purpose of a web browser (Chrome, IE, Firefox, Safari) is to read HTML documents and display them.
The browser does not display the HTML tags, but uses them to determine how to display the document:
HTML Page Structure
Below is a visualization of an HTML page structure:
Only the <body> section (the white area above) is displayed in a browser.
The <!DOCTYPE> Declaration
The <!DOCTYPE> declaration represents the document type, and helps the browser to display a web page correctly.
It must only appear once, at the top of the page (before any HTML tags).
There are different document types. To display a web page correctly, the browser must know both type and version.
The doctype declaration is not case sensitive. All cases are acceptable:
Common <!DOCTYPE> Declarations
All tutorials and examples at W3Schools use HTML5.
Since the early days of the web, there have been many versions of HTML: