There are several doctype declarations in html5-Front-end Q&A-php.cn

Home

Web Front-end

Front-end Q&A

There are several doctype declarations in html5

青灯夜游

Nov 17, 2021 pm 02:41 PM

html5

html5 has only one doctype declaration, the syntax "<!DOCTYPE HTML>"; and the "<!DOCTYPE>" declaration must be located in the first line of the HTML5 document, that is, in "<html> ” tag, it tells the browser that the document uses the HTML specification.

There are several doctype declarations in html5

The operating environment of this tutorial: Windows 7 system, HTML5 version, Dell G3 computer.

doctype declaration in html5

There are three <!DOCTYPE> declarations in HTML 4.01, but there is only one in HTML 5, And it's very simple: the

<!DOCTYPE HTML>

Copy after login

<!DOCTYPE> declaration must be on the first line in the HTML5 document, before the <html> tag. This tag tells the browser the HTML specification used by the document.

The doctype declaration is not an HTML tag, it is an instruction that tells the browser the version of markup used to write the page.

It is very important to specify the doctype in all HTML documents so that the browser understands the expected document type.

<!DOCTYPE> The tag has no closing tag and is not case-sensitive.

Extended knowledge: doctype declarations in HTML 4.01

HTML 4.01 Strict

The DTD Contains all HTML elements and attributes, except presentational and deprecated elements (such as font). Framesets are not allowed.

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

Copy after login

HTML 4.01 Transitional

This DTD contains all HTML elements and attributes, including presentational and deprecated elements (such as font) . Framesets are not allowed.

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

Copy after login

HTML 4.01 Frameset

This DTD is equivalent to HTML 4.01 Transitional, but allows frameset content.

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

Copy after login

Recommended tutorial: "html video tutorial"

The above is the detailed content of There are several doctype declarations in html5. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn