!doctype

Document type declaration (doctype) is a declaration of the type of HTML document.

Syntax

<!DOCTYPE top-element availability "registration//organization//type label//definition language" "uniform-resource-locator">
Name Default Description
top element html top-level element
availability PUBLIC formal public identifier (FPI) is a publicly accessible object or a system resource
PUBLIC specifies a publicly accessible object
SYSTEM specifies a system resource, such as a local file or URL
registration + registered by the International Organization for Standardization (ISO)
+ specifies registered
- specifies not registered
organization OwnerID, a unique label indicating the name of the organization responsible for creation and maintenance of the DTD
type DTD public text class, the type of object being referenced
label HTML public text description, a unique descriptive name for the public text being referenced
definition document type definition (DTD)
Strict specifies non-depreciated and non-frame elements and attributes
Transitional specifies depreciated and non-frame elements and attributes
Frameset specifies depreciated and frame elements and attributes
language EN public text language, the natural language encoding system used in the creation of the referenced object
uniform resource locator location of the referenced object

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">

XHTML 1

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 Basic 1.1

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.1//EN" "http://www.w3.org/TR/xhtml-basic/xhtml-basic11.dtd">

HTML5

<!DOCTYPE html>

Example

External

Microsoft doctype

W3C doctype

W3C HTML 4.01 Specification

W3C HTML5

W3C HTML 5.1