Skip to main content

DOCTYPE in HTML – What Is a Document Type Declaration?

A DOCTYPE declaration informs browsers about a document's type and version.

Example of an HTML Document with a Doctype Declaration

The <!DOCTYPE html> preamble in the snippet below tells web browsers that the page is an HTML5 document type.

<!DOCTYPE html>
<html>
  <head>
    <title>Your document's title</title>
  </head>
  <body>
    <!-- Space for the documents's content such as <p>, <div>, and <img> elements -->
  </body>
</html>

Note the following:

A <!DOCTYPE> declaration is not an HTML tag. It is a preamble for declaring information about a document to web browsers.
It is essential to declare your document type before defining other HTML elements.
The <!DOCTYPE> declaration is case-insensitive. So, browsers interpret <!DOCTYPE>, <!doctype>, <!Doctype>, and <!DocType> as equivalent document type declarations.

Overview

The article discussed what a <!DOCTYPE> is. We also used an example to understand how to define it in an HTML document.

Example of an HTML Document with a Doctype Declaration
Overview