Document Type Declarations

Hypertext Markup Language (HTML)

HTML is the most common language used for creating websites.

HTML 2.0

<!DOCTYPE html PUBLIC "-//IETF//DTD HTML 2.0//EN">

HTML 3.2

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">

HTML ISO

<!DOCTYPE HTML PUBLIC "ISO/IEC 15445:2000//DTD HyperText Markup Language//EN">

HTML 4.01

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

eXtensible Markup Language (XML)

XML is a metalanguage, a markup language that is used to create other languages. These declarations are a little bit different due to its nature. One must explain which version of XML is being used, then what the actual markup language is.

XML 1.0: <?xml version="1.0" encoding="utf-8"?>

eXtensible Hypertext Markup Language (XHTML)

XHTML is HTML reformatted as an XML application.

XHTML 1.0

Strict: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
Transitional: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
Frameset: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">

XHTML 1.1

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

XHTML namespace: http://www.w3.org/1999/xhtml

Math Markup Language (MathML)

MathML is an XML-based language used for displaying mathematical formulae.

MathML 1.1: <!DOCTYPE math SYSTEM "http://www.w3.org/Math/DTD/mathml1/mathml.dtd">
MathML 2.0: <!DOCTYPE math PUBLIC "-//W3C//DTD MathML 2.0//EN" "http://www.w3.org/TR/MathML2/dtd/mathml2.dtd">

MathML namespace: http://www.w3.org/1998/Math/MathML

Synchronized Multimedia Integration Language (SMIL)

SMIL is an XML-based language used for creating audiovisual presentations, such as animations.

SMIL 1.0: <!DOCTYPE smil PUBLIC "-//W3C//DTD SMIL 1.0//EN" "http://www.w3.org/TR/REC-smil/SMIL10.dtd">
SMIL 2.0: <!DOCTYPE smil PUBLIC "-//W3C//DTD SMIL 2.0//EN" "http://www.w3.org/2001/SMIL20/SMIL20.dtd">
SMIL 2.1: <DOCTYPE smil PUBLIC "-//W3C//DTD SMIL 2.1//EN" "http://www.w3.org/2005/SMIL21/SMIL21.dtd">

SMIL namespace: http://www.w3.org/ns/SMIL

Scalable Vector Graphics (SVG)

SVG is an XML-based language used for creating graphics.

SVG 1.0: <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.0//EN" "http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd">
SVG 1.1 Full: <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
SVG 1.1 Basic: <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1 Basic//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11-basic.dtd">
SVG 1.1 Tiny: <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1 Tiny//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11-tiny.dtd">

SVG namespace: http://www.w3.org/2000/svg

XHTML Plus _____

Being XML, XHTML 1.1 can be mixed with other XML-Based languages.

XHTML + MathML

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1 plus MathML 2.0//EN" "http://www.w3.org/Math/DTD/mathml2/xhtml-math11-f.dtd">

XHTML + MathML + SVG

XHTML as the host language: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1 plus MathML 2.0 plus SVG 1.1//EN" "http://www.w3.org/2002/04/xhtml-math-svg/xhtml-math-svg.dtd">
Using SVG as the host: <!DOCTYPE svg:svg PUBLIC "-//W3C//DTD XHTML 1.1 plus MathML 2.0 plus SVG 1.1//EN" "http://www.w3.org/2002/04/xhtml-math-svg/xhtml-math-svg.dtd">

XHTML + SMIL

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML+SMIL //EN" "http://www.w3.org/2001/SMIL20/WD/xhtmlplussmil.dtd">