WEB standards are not a single standard, but a collection of standards. A web page mainly consists of three parts: Structure, Presentation and Behavior. The corresponding standards are also divided into three aspects: structured standard languages mainly include XHTML and XML, performance standard languages mainly include CSS, and behavioral standards mainly include object models (such as W3C DOM), ECMAScript, etc. Most of these standards are drafted and published by W3C, and some are standards developed by other standards organizations, such as the ECMAScript standard of ECMA (European Computer Manufacturers Association). Let’s take a brief look at these standards: 1． structured standard language (1)XML XML is the abbreviation of The Extensible Markup Language. The current recommendation is XML1.0 released by W3C on October 6, 2000, reference (www.w3.org/TR/2000/REC-XML-20001006). Like HTML, XML also comes from SGML, but XML is a language that can define other languages. XML was originally designed to make up for the shortcomings of HTML and meet the needs of network information release with strong scalability. It was later gradually used for the conversion and description of network data. I won’t go into details about the benefits and technical specifications of XML here. There is a lot of information on the Internet and many books for reference. (2)XHTML XHTML is the abbreviation of The Extensible HyperText Markup Language. The current recommendation is to follow the W3C recommendation of XML1.0 on January 26, 2000 (refer to http://www.w3.org/TR/xhtml1). 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 sites. Therefore, based on HTML4.0, we extended it with XML rules and obtained XHTML. Simply put, the purpose of establishing XHTML is to realize the transition from HTML to XML. 2. Express standard language CSS is the abbreviation of Cascading Style Sheets. The current recommendations follow the W3C recommendation of CSS2 on May 12, 1998 (refer to http://www.w3.org/TR/CSS2/). The W3C created the CSS standard to replace HTML table layout, frames, and other presentation languages with CSS. The combination of pure CSS layout and structured XHTML can help designers separate appearance and structure, making the site easier to access and maintain. 3. Standards of conduct (1)DOM DOM is the abbreviation of Document Object Model. According to the W3C DOM specification (http://www.w3.org/DOM/), DOM is an interface with browsers, platforms, and languages that allows you to access other standard components of the page. Simply understood, DOM resolves the conflict between Netscaped's Javascript and Microsoft's Jscript, giving web designers and developers a standard way to access data, scripts, and presentation layer objects in their sites. (2) ECMAScript ECMAScript is a standard scripting language (JAVAScript) developed by ECMA (European Computer Manufacturers Association). The current recommendation is to follow ECMAScript 262 (http://www.ecma.ch/ecma1/STAND/ECMA-262.HTM).