File extension

.html

HTML 2.0 (RFC 1866 approved by IETF)

.html files are HyperText Markup Language documents: the tag-based markup language that structures the content of web pages, linking text, media, and interactive elements for display in browsers.

Known meanings

Formats and reference material for .html

HTML 2.0 (RFC 1866 approved by IETF)

HTML 2.0 (RFC 1866 approved by IETF)

  • internet
Open link

HTML 3.2 Specification (W3C approved)

HTML 3.2 Specification (W3C approved)

  • internet
  • Dave Raggett
Open link

HTML 4 Specification (W3C approved)

HTML 4 Specification (W3C approved)

  • internet
  • Dave Raggett
Open link

HTML 4.01 Specification (W3C approved)

HTML 4.01 Specification (W3C approved)

  • internet
Open link

Details

Format notes

HyperText Markup Language (HTML)

HTML is the markup language that defines the structure and content of documents on the World Wide Web. An HTML file is text marked up with elements written as tags — such as <p>, <a>, <img>, <table>, and <div> — that describe headings, paragraphs, links, images, forms, and other content. Browsers parse this markup into a document tree (the DOM) and render it, typically combined with CSS for presentation and JavaScript for behavior.

HTML has a long standardization history: early versions were specified by the IETF (HTML 2.0) and then the W3C (HTML 3.2, 4.0, 4.01, and the XML-serialized XHTML). Development is now stewarded by the WHATWG as the continuously updated “HTML Living Standard” rather than numbered releases, which is the current authoritative definition.

Structure And Robustness

A modern document starts with <!DOCTYPE html> and nests content inside <html>, <head>, and <body>. A defining trait of HTML is lenient parsing: browsers apply well-defined error-recovery rules to malformed markup, so pages render even when tags are unclosed or misnested. This forgiving behavior is a major difference from strict XML-based formats.

Preservation And Security Notes

The media type is text/html, conventionally UTF-8 encoded. HTML is good for preservation as open, documented text, but a page’s appearance depends on external CSS, scripts, fonts, and images, so archiving should capture those dependencies. Because HTML routinely carries active content, systems that display untrusted HTML must sanitize it to prevent cross-site scripting (XSS) and control what scripts, embeds, and external requests are allowed.

Further Reading

  • HTML Living Standard (WHATWG): https://html.spec.whatwg.org/
  • MDN HTML documentation: https://developer.mozilla.org/docs/Web/HTML