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
Example
<!DOCTYPE html>
<html>
<head>
<title>Page Title</title>
</head>
<body>
<h1>My First Heading</h1>
<p>My first paragraph.</p>
</body>
</html>
Example Explained
-
- 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
HTML Tags
HTML tags ar keywords (tag names) surrounded by angle brackets:
<tagname>content goes here...</tagname>
-
- HTML tages normally come in pairs like <p> and </p>
- The first tag in 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
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 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>
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:
<!DOCTYPE html>
<!doctype HTML>
Common <!DOCTYPE> Declarations
HTML5 <!DOCTYPE HTML>
HTML4.01 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd"
XHTML1.0 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
HTML Versions
Version Year
HTML 1991
HTML2.0 1995
HTML3.2 1997
HTML4.01 1999
XHTML 2000
HTML5 2014