XHTML tutorial, simple understanding of the basic knowledge of XHTML_HTML/Xhtml_Web page production

This article will briefly introduce you to XHTML and understand the basic knowledge of XHTML
What is XHTML
XHTML is the abbreviation of The Extensible HyperText Markup Language. HTML is a basic WEB web page design language. XHTML is a markup language based on XML. It looks somewhat similar to HTML, with only some small but important differences. XHTML is an XML that plays a role similar to HTML. So, in essence, XHTML is a transitional technology that combines some of the powerful features of XML with most of the simple features of HTML.
At the end of 2000, the international W3C (World Wide Web Consortium) organization announced the release of XHTML version 1.0. XHTML 1.0 is a new language optimized and improved on the basis of HTML 4.0, aiming at XML-based applications. XHTML is an enhanced HTML, and its scalability and flexibility will adapt to more needs of future network applications. Although XML has powerful data conversion capabilities and can completely replace HTML, it is still too early to directly adopt XML in the face of thousands of existing websites designed based on HTML language. Therefore, on the basis of HTML4.0, we extended it with XML rules and obtained XHTML. Therefore, the purpose of establishing XHTML is to realize the transition from HTML to XML. The currently respected WEB standard in website design internationally is XHTML-based application (commonly known as CSS+DIV).
XHTML version
Up to now, XHTML has the following versions:
　XHTML 1.0 Transitional
XHTML 1.0 strict
　XHTML 1.0 Frameset
XHTML 1.1
XHTML Basics
Among them, "XHTML 1.0 Transitonal" is adapted from "HTML 4.01 Transitional", "XHTML 1.0 Strict" is adapted from "HTML 4.01 Strict", and "XHTML 1.0 Frameset" is adapted from "HTML 4.01 Frameset".
The small text comment tags added in Microsoft Internet Explorer 5.0 are supported in XHTML 1.1 (see Ruby characters).
XHTML Syntax
The XHTML language must conform to the format of XML. For example, it must be written and used with a closing paragraph. Moreover, XHTML tags must use lowercase letters, such as cannot be written as; each attribute must be enclosed in quotation marks, such as must be used but cannot be used. The purpose of these practices is to enable an XHTML web page to be compiled correctly and quickly by web browsers.