HTML Introduction

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

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HTML Example

A small HTML document:

<!DOCTYPE html>
<html>
<head>
<title>Page Title</title>
</head>
<body>

<h1>My First Heading</h1>
<p>My first paragraph.</p>

</body>
</html>

Try it Yourself >>

Example Explained

• The DOCTYPE declaration defines the document type to be HTML
• 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 can display a document with a heading and a paragraph.

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HTML Tags

HTML tags are keywords (tag names) surrounded by angle brackets:

<tagname>content</tagname>

• 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 slash before the tag name

Note: The start tag is often called the opening tag. The end tag is often called the closing tag.

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Web Browsers

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:

<html>

<head>

<title>Page title</title>

</head>

<body>

<h1>This is a heading</h1>

<p>This is a paragraph.</p>

<p>This is another paragraph.</p>

</body>

</html>

Note:  Only the <body> area (the white area) is displayed by the browser.

The <!DOCTYPE> Declaration

The <!DOCTYPE> declaration helps the browser to display a web page correctly.

There are different document types on the web.

To display a document correctly, the browser must know both type and version.

The doctype declaration is not case sensitive. All cases are acceptable:

<!DOCTYPE html>

<!DOCTYPE HTML>

<!doctype html>

<!Doctype Html>

Common Declarations

HTML5

<!DOCTYPE html>

HTML 4.01

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

XHTML 1.0

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

HTML Versions

Since the early days of the web, there have been many versions of HTML:

Version	Year
HTML	1991
HTML 2.0	1995
HTML 3.2	1997
HTML 4.01	1999
XHTML	2000
HTML5	2014