The !doctype HTML element declares the type of document.

It is case-insensitive and placed at the start of the document.


<!doctype top-element availability "registration//organization//type label definition//language" "uniform-resource-locator">
top elementhtmltop-level element
availabilityPUBLICformal 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
organizationOwnerID, a unique label indicating the name of the organization responsible for creation and maintenance of the DTD
typeDTDpublic text class, the type of object being referenced
labelHTMLpublic text description, a unique descriptive name for the public text being referenced
definitiondocument 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
languageENpublic text language, the natural language encoding system used in the creation of the referenced object
uniform resource locatorlocation of the referenced object


<!doctype html PUBLIC "-//W3C//DTD HTML 4.0//EN">
<!doctype html PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">
<!doctype html PUBLIC "-//W3C//DTD HTML 4.0 Frameset//EN" "http://www.w3.org/TR/REC-html40/frameset.dtd">
<!doctype html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">

HTML 4.01

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


<!doctype html>


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


<!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">