Standards

Standards and guidelines assist in optimization for search engines and screen readers. HTML5 semantic elements provide the mechanisms necessary to structure the page more easily for accessibility via screen readers. Search engines take advantage of HTML5 semantics by using the article element to determine the purpose of the page.

Language Specifications

Elements, attributes, and attribute values in HTML are defined in the Specification, to have certain meanings (semantics). These definitions allow HTML processors, like web browsers and search engines, to present documents and applications consistently in different contexts.
🔗 All standards & drafts. — W3Consortium (w3.org)
🔗 HTML Living Standard — Last Updated 5 January 2022 (whatwg.org)

Well-formed and valid code

Well-formed code refers to compliance to standards, including

  • closing all elements

  • nesting elements properly

  • using correct syntax for attributes

Validity refers to eliminating all syntax and semantic errors. This can be done by using the validation tools available from W3C.

Validator tools

Web taxonomy and status
Specifications

HTML5 APIs and related technologies; note this diagram has been prepared a few years ago. Consult the specifications and the standards organizations for updates and current status on the individual components.

The World Wide Web Consortium (W3C) is an international community where Member organizations, a full-time staff, and the public work together to develop Web standards. Led by Web inventor and Director Tim Berners-Lee and CEO Jeffrey Jaffe, W3C's mission is to lead the Web to its full potential. W3C standards define an Open Web Platform for application development that has the unprecedented potential to enable developers to build rich interactive experiences.

Read further about W3 Consortium standards.

The Web Hypertext Application Technology Working Group (WHATWG) is a community of people interested in evolving the web through standards and tests. The WHATWG was founded by individuals of Apple, the Mozilla Foundation, and Opera Software in 2004, after a W3C workshop. In 2017, Apple, Google, Microsoft, and Mozilla helped develop an IPR policy and governance structure for the WHATWG, together forming a Steering Group to oversee relevant policies.

Read further about WHATWG standards.