Official Specifications
Official Specifications
Section titled “Official Specifications”The web platform is defined by open standards. This page links to the official specifications that define HTML, CSS, accessibility, and web APIs.
HTML and Standards Bodies
Section titled “HTML and Standards Bodies”WHATWG (Web Hypertext Application Technology Working Group)
Section titled “WHATWG (Web Hypertext Application Technology Working Group)”The WHATWG maintains the HTML Living Standard, the de facto specification that browser vendors follow.
HTML Living Standard The official, continuously updated HTML specification maintained by WHATWG. This is what browsers implement.
DOM Living Standard Specification for the Document Object Model (DOM) that JavaScript interacts with.
Fetch Living Standard Defines the Fetch API and how browsers make HTTP requests.
URL Living Standard Specification for URL parsing and handling.
W3C (World Wide Web Consortium)
Section titled “W3C (World Wide Web Consortium)”W3C develops complementary standards and recommendations for web technologies.
W3C HTML Specification W3C's version of the HTML specification, maintained in parallel with WHATWG.
Web Performance Working Group Standards for measuring and improving web performance.
Cascading Style Sheets (CSS) Official CSS specifications and drafts.
W3C Web Security Standards for web security, including CORS, CSP, and authentication.
Accessibility Standards
Section titled “Accessibility Standards”ARIA (Accessible Rich Internet Applications)
Section titled “ARIA (Accessible Rich Internet Applications)”ARIA provides a way to make web applications more accessible to people with disabilities.
ARIA Authoring Practices Guide Best practices for implementing accessible rich internet applications with examples and patterns.
ARIA Specification The official ARIA specification defining roles, properties, and states.
ARIA Roles, States, and Properties Complete reference of all ARIA attributes and their uses.
WCAG (Web Content Accessibility Guidelines)
Section titled “WCAG (Web Content Accessibility Guidelines)”WCAG defines criteria for accessible web content at three conformance levels: A, AA, and AAA.
WCAG 2.1 Specification The international standard for web accessibility. Currently the most widely adopted version.
WCAG 2.2 Specification The latest version of WCAG with updated guidance for modern web applications.
Understanding WCAG 2.1 Detailed explanations and examples of each WCAG success criterion.
Web Content Accessibility Guidelines — Overview Introduction to WCAG and how to use it.
JavaScript and Web APIs
Section titled “JavaScript and Web APIs”ECMAScript (JavaScript Language)
Section titled “ECMAScript (JavaScript Language)”The official JavaScript language standard maintained by TC39.
ECMAScript 2024 (ES15) Specification The latest official JavaScript language specification.
TC39 Proposals Upcoming JavaScript features being proposed and discussed.
Web APIs
Section titled “Web APIs” MDN Web Docs — Web APIs Comprehensive reference for all Web APIs available in browsers.
WebAssembly Specification Binary instruction format for the web. Enables high-performance applications.
Service Worker Specification APIs for service workers, enabling offline-first and progressive web applications.
Web Components Standards for Custom Elements, Shadow DOM, and HTML Templates.
CSS Specifications
Section titled “CSS Specifications”CSS Module Specifications
Section titled “CSS Module Specifications”CSS is organized into modules, each covering specific features.
CSS Selectors Level 3 Complete specification of CSS selector syntax.
CSS Box Model Defines how content, padding, borders, and margins work in CSS.
CSS Flexible Box Layout The Flexbox specification for flexible layouts.
CSS Grid Layout The Grid specification for two-dimensional layouts.
CSS Positioned Layout Specification for absolute, relative, and fixed positioning.
CSS Transforms Specification for CSS transforms (rotate, scale, translate, etc.).
CSS Transitions Specification for CSS transitions and animations.
Media and Embedding Standards
Section titled “Media and Embedding Standards” Media Queries Specification Specification for responsive design media queries.
Picture Element Specification Defines the element for responsive images.
WebVideo Codec Specifications Recommendations for video and audio codecs on the web.
Security Specifications
Section titled “Security Specifications” Content Security Policy (CSP) Specification for controlling which resources can be loaded on a page.
Cross-Origin Resource Sharing (CORS) Specification for secure cross-origin HTTP requests.
Subresource Integrity (SRI) Specification for verifying the integrity of resources.
Web Authentication (WebAuthn) Standard for secure, passwordless authentication.
Performance Specifications
Section titled “Performance Specifications” Navigation Timing API APIs for measuring page load performance.
Resource Timing API APIs for measuring individual resource load performance.
Performance Observer API API for observing performance metrics in real-time.
Largest Contentful Paint (LCP) Web Vitals metric specification.
Structured Data
Section titled “Structured Data” Schema.org Collaborative, community activity with a mission to create, maintain, and promote schemas for structured data.
JSON-LD Specification JSON for Linking Data — recommended format for adding structured data to web pages.
Open Graph Protocol Standard for adding metadata to web pages for social sharing.
Comprehensive Resources
Section titled “Comprehensive Resources” MDN Web Docs Mozilla's comprehensive documentation for web technologies, maintained by the community.
W3C Standards Index Complete list of all W3C standards and recommendations.
WHATWG Standards Index Complete list of all WHATWG standards.
Can I Use Browser support tables for web features.