Good Morning to all,
Today I share one useful topic related to <!DOCTYPE html >.
The doctype declaration is <!DOCTYPE html> should be the very first thing in an HTML document, before the tag and is case-insensitive in html syntax.
<!DOCTYPE html> goes at the top of every HTML5 page. The HTML syntax of HTML5 requires a DOCTYPE to be specified to ensure that the browser renders the page in standards mode. The DOCTYPE has no other purpose and is therefore optional for XML. Documents with an XML media type are always handled in standards mode. [DOCTYPE]
Example
Title of the document .... Content ....
Common DOCTYPE Declarations
HTML 5
<!DOCTYPE html>
HTML 4.01 Strict
This DTD contains all HTML elements and attributes, but does NOT INCLUDE presentational or deprecated elements (like font).
Framesets are not allowed.
<!DOCTYPE HTML PUBLIC “-//W3C//DTD HTML 4.01//EN” “http://www.w3.org/TR/html4/strict.dtd”>
HTML 4.01 Transitional
This DTD contains all HTML elements and attributes, INCLUDING presentational and deprecated elements (like font).
This declares the document to be HTML 4.01 Transitional. HTML 4 Transitional includes all elements and attributes of HTML 4 Strict.
<!DOCTYPE HTML PUBLIC “-//W3C//DTD HTML 4.01 Transitional//EN” “http://www.w3.org/TR/html4/loose.dtd”>
HTML 4.01 Frameset
This DTD is equal to HTML 4.01 Transitional, but allows the use of frameset content.
<!DOCTYPE HTML PUBLIC “-//W3C//DTD HTML 4.01 Frameset//EN” “http://www.w3.org/TR/html4/frameset.dtd”>
XHTML 1.0 Strict
This DTD contains all HTML elements and attributes, but does NOT INCLUDE presentational or deprecated elements (like font).
<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Strict//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd”>
XHTML 1.0 Transitional
This DTD contains all HTML elements and attributes, INCLUDING presentational and deprecated elements (like font).
<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd”>
XHTML 1.0 Frameset
This DTD is equal to XHTML 1.0 Transitional, but allows the use of frameset content.
<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Frameset//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd”>
XHTML 1.1
This DTD is equal to XHTML 1.0 Strict, but allows you to add modules (for example to provide ruby support for East-Asian languages).
<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.1//EN” “http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd”>
<!DOCTYPE html> goes at the top of every HTML5 page.