A front-end interview frequently asked questions --- W3C standard

W3C standard consists of structured standard language, performance standard language, and behavioral standards.

It doesn't just refer to a certain standard, but a collection of standards. The web page is mainly composed of three parts: Structure, Presentation, and Behavior. The corresponding standards are also divided into three aspects: the structured standard language mainly includes XHTML and XML, the performance standard language mainly includes CSS, and the behavioral standards mainly include object models (such as W3C DOM) and ECMAScript. Most of these standards are drafted and published by the W3C, and some are standards developed by other standards organizations, such as the ECMA (European Computer Manufacturers Association) ECMAScript standard. Let's take a brief look at these standards:

1, Structured Standard Language:

1XML Language

XML is short for The Extensible Markup Language. The current recommendation is to follow the XML 1.0 released by the W3C on October 6, 2000, with reference (www.w3.org/TR/2000/REC-XML-20001006). Like HTML, XML is also derived from SGML, but XML is a language that can define other languages. The original purpose of XML was to make up for the shortcomings of HTML, to meet the needs of network information distribution with strong scalability, and then gradually used for the conversion and description of network data. The benefits of XML and the technical specifications are not mentioned here. There are a lot of information on the Internet, and there are many books for reference.

2XHTML language

XHTML is an acronym for The Extensible HyperText Markup Language Extensible Markup Language. Currently recommended to follow the W3C recommended XML1.0 on January 26, 2000. XML, although powerful in data conversion, can completely replace HTML, but in the face of thousands of existing sites, it is too early to adopt XML directly. Therefore, based on HTML4.0, we extend it with XML rules and get XHTML. Simply put, the purpose of creating XHTML is to achieve the transition from HTML to XML.

2, Performance Standard Language

CSS is an abbreviation for Cascading Style Sheets. It is currently recommended that the W3C recommend CSS2 on May 12, 1998 (see http://www.w3.org/TR/CSS2/). The purpose of the W3C to create CSS standards is to replace the HTML table format layout, frames, and other performance languages ​​with CSS. The combination of pure CSS layout and structured XHTML helps designers separate the look and structure, making site access and maintenance easier.

3, Behavior Standard


DOM is an abbreviation of Document Object Model Document Object Model. According to the W3C DOM specification (http://www.w3.org/DOM/), DOM is an interface to browsers, platforms, and languages ​​that allows you to access other standard components of the page. To put it simply, DOM solves 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.


ECMAScript is the standard scripting language (JAVAScript) developed by the ECMA (European Computer Manufacturers Association). It is currently recommended to follow ECMAScript 262 (http://www.ecma.ch/ecma1/STAND/ECMA-262.HTM).