Question

what do you mean by DOCTYPE​

Answer 1

Answer:

A Document Type Declaration, or DOCTYPE for short, is an instruction to the web browser about the version of markup language in which a web page is written. With HTML5 this is no longer the case and the doctype declaration is only needed to enable the standard mode for documents written using the HTML syntax.

Answer 2

Answer:

document type declaration

Explanation:

A .document type declaration, or DOCTYPE, is an instruction that associates a particular XML or SGML document (for example, a webpage) with a document type definition (DTD) (for example, the formal definition of a particular version of HTML 2.0 - 4.0).