Summary of DTD usage in html_HTML/Xhtml_Web page production-HTML Tutorial-php.cn

DTD is a set of syntax rules for tags. It is part of the XML1.0 version specification, is the verification mechanism of html files, and is part of the composition of html files.

DTD: three document types: S (Strict), T (Transitional), F (Frameset).
Strict: Use this type if you need clean markup without clutter in the presentation layer. Please use with Cascading Style Sheets (CSS)
Transitional: The DTD can contain rendering attributes and elements that the W3C expects to be moved into the style sheet. Use
Frameset if your readers are using browsers that don't support Cascading Style Sheets (CSS) and you have to use HTML's rendering features: DTD should be used for documents with frames. Except that the frameset element replaces the body element, Frameset DTD is equivalent to Transitional DTD

html5 basically does not have the strict requirements of XHTML 1.0 Transitional, and simplifies many things and can be used directly

HTML5

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xhtml 1.1:

xhtml 1.1 plus mathml plus svg:

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html 4.01 strict:

html 4.01 transitional:

html 4.01 frameset:

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xhtml 1.0 strict:

xhtml 1.0 transitional:

xhtml 1.0 frameset:

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html 3.2:

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html 2 (the number 2 represents the version number):

Attached is a comparison of the old version tags with the DTD document:

Tags	Description	DTD
	Define the document type.	STF
	Define HTML document.	STF
	Define the body of the document.	STF
to	Define HTML title.	STF
	Define paragraph.	STF
	Define simple line breaks.	STF
	Define the horizontal line.	STF
	Define annotation.	STF

Tags	Description	DTD
	Define bold text.	STF
	Deprecated. Define text font, size and color	TF
	Define italic text.	STF
	Define emphasis text.	STF
	Define large text.	STF
	Define emphasis text with a stronger tone.	STF
	Define small text.	STF
	Define superscript text.	STF
	Define subscript text.	STF
	Define the direction of the text.	STF
	Deprecated. Defines underlined text.	TF

标签	描述	DTD
	定义预格式文本	STF
	定义计算机代码文本。	STF
	定义打字机文本。	STF
	定义键盘文本。	STF
	定义文本的变量部分。	STF
	定义定义项目。	STF
	定义计算机代码样本。	STF