A doctype, or document type declaration, is an instruction that associates a particular document with a Document Type Definition (DTD). In the context of web development, it is a declaration at the beginning of an HTML or XML document that informs the web browser about the version of HTML or XML the document is written in.
The doctype helps the browser to render the content correctly by understanding the version and type of markup language being used. It ensures that the web page is displayed in a consistent way across different browsers by triggering the correct rendering mode.
Example in HTML: The doctype declaration is required for HTML documents to be correctly parsed and rendered by web browsers. Here is an example of the doctype declaration for HTML5:
<!DOCTYPE html>
<html>
<head>
<title>Example Document</title>
</head>
<body>
<p>Hello, World!</p>
</body>
</html>```