HTML

1 program Added 2026-03-12T10:00:00Z Agent: claude-codeModel: claude-sonnet-4-6WebSearch: disabled Evidence Report issue View issues
Aliases: HyperText Markup Language, HTML5
Provenance: commit e2cec8a557 · authored 2026-03-12T00:22:31+01:00 · agent claude-code · model claude-sonnet-4-6

Sources mentioning this language

7 sources · pl_id: pl/html
LLM (this repo) · 1PldbLinguistPygmentsWikipediaHyperpolyglotWikidata · Q8811

Wikipedia infobox

Pulled from the wikimedia/structured-wikipedia snapshot — see data/raw/wikipedia_pl_facts.*.jsonl and pl_fact.csv for the long-table provenance.

Designed byWHATWG · World Wide Web Consortium (W3C · formerly)
First appeared1993
Homepagehttps://html.spec.whatwg.org/

Extensions claimed by this language

12 claims. Each row is one upstream assertion with its strength. SWH column shows file occurrences with that extension across the entire archive.
ExtensionSourceStrengthSWH
.htmwikidataprimary34.8M files
.htmllinguistprimary2.8B files
.htmlpygmentsprimary2.8B files
.htmlwikidataprimary2.8B files
.htalinguistsecondary18.4K files
.htmlinguistsecondary34.8M files
.htmpygmentssecondary34.8M files
.inclinguistsecondary6.3M files
.xhtlinguistsecondary240.1K files
.xhtmllinguistsecondary7.3M files
.xhtmlpygmentssecondary7.3M files
.xsltpygmentssecondary217.5K files

Related languages

TTML (0.40)HVML (0.38)MJML (0.36)YAML (0.36)RuleML (0.36)

LLM-contributed programs

Hello World

Provenance: commit e2cec8a557 · authored 2026-03-12T00:22:31+01:00 · agent claude-code · model claude-sonnet-4-6 · WebSearch disabled
code.html · license: CC0-1.0 · added: 2026-03-12T10:00:00Z
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Hello World</title>
</head>
<body>
    <h1>Hello, World!</h1>
    <p>Welcome to my first HTML page.</p>
    <ul>
        <li>First item</li>
        <li>Second item</li>
        <li>Third item</li>
    </ul>
</body>
</html>

Real programs from Software Heritage

1 sample mined from derived_datasets/<date>/contents/*.parquet, byte-verified against the SWH archive. Citation-grade qualified SWHIDs preserved.
abs-pos-non-replaced-vlr-113.xht · 3075 B · ext .xht · seen 569× in SWH
via fallback
swh:1:cnt:3c1f881a66bd575144cf536f4c15cc304cf38d73;origin=https://github.com/adamlaska/web-platform-tests-wpt;anchor=swh:1:rev:1f0d8835edeba24238ee4ab1ca1079edf2449f03;path=/css/css-writing-modes/abs-pos-non-replaced-vlr-113.xht
Open in SWH · Raw bytes (SWH) · GitHub raw
Show source
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

 <head>

  <title>CSS Writing Modes Test: absolutely positioned non-replaced element - 'direction: rtl' and 'top', 'height', and 'bottom' are 'auto'</title>

  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/" />
  <link rel="help" href="http://www.w3.org/TR/css-writing-modes-3/#vertical-layout" title="7.1 Principles of Layout in Vertical Writing Modes" />
  <link rel="help" href="http://www.w3.org/TR/CSS21/visudet.html#abs-non-replaced-height" title="10.6.4 Absolutely positioned, non-replaced elements" />
  <link rel="match" href="abs-pos-non-replaced-vlr-009-ref.xht" />

  <meta name="flags" content="ahem image" />
  <meta name="assert" content="When 'direction' is 'rtl' and 'top', 'height' and 'bottom' are 'auto', then set 'top' to the static position, the height is based on content and then solve for 'bottom'." />

  <style type="text/css"><![CDATA[
  div#containing-block
    {
      background: red url("support/bg-red-2col-2row-320x320.png");
      color: transparent;
      direction: rtl;
      font: 80px/1 Ahem;
      height: 320px;
      position: relative;
      width: 320px;
    }

  div#containing-block > span
    {
      background-color: red;
      bottom: auto;
      color: green;
      height: auto;
      position: absolute;
      top: auto;
      writing-mode: vertical-lr;
    }

/*
"
If all three of 'top', 'height', and 'bottom' are auto, set 'top' to the static position and apply rule number three below.

3. 'height' and 'bottom' are 'auto' and 'top' is not 'auto', then the height is based on the content per 10.6.7, set 'auto' values for 'margin-top' and 'margin-bottom' to 0, and solve for 'bottom'
"

'top' + 'margin-top' + 'border-top-width' + 'padding-top' + 'height' + 'padding-bottom' + 'border-bottom-width' + 'margin-bottom' + 'bottom' = height of containing block

So:

     80px : top: auto: set to static position
  +
      0px : margin-top
  +
      0px : border-top-width
  +
      0px : padding-top
  +
  (shrink-to-fit) : height: auto
  +
      0px : padding-bottom
  +
      0px : border-bottom-width
  +
      0px : margin-bottom
  +
  (solve) : bottom: auto
    =====================
    320px : height of containing block

gives us:

     80px : top: auto: set to static position
  +
      0px : margin-top
  +
      0px : border-top-width
  +
      0px : padding-top
  +
     80px : (shrink-to-fit) : height: auto
  +
      0px : padding-bottom
  +
      0px : border-bottom-width
  +
      0px : margin-bottom
  +
  (solve) : bottom: auto
    =====================
    320px : height of containing block

And so computed bottom value must be 160px .
*/

  ]]></style>

 </head>

 <body>

  <p><img src="support/pass-cdts-abs-pos-non-replaced.png" width="246" height="36" alt="Image download support must be enabled" /></p>

  <div id="containing-block">1 2 34<span>X</span></div>

 </body>
</html>

Disambiguation rules

Linguist heuristic rules that predict this language when one of its claimed extensions is shared with another.
RuleExtKindPredicates (truncated)
h/linguist/.html/1.htmldefault[]

Contribute — propose a file extension

Tell us where to find evidence about HTML (mapped to pl/html). A reference URL is required; at least one of extension or program code must be provided too. A maintainer reviews each submission via a draft PR before anything lands.
Optional: attach a program from that URL
If the reference URL points at a single source file you'd like to add as an example program, paste it below. The workflow will write it under languages/HTML/programs/<sha>/. Keep under ~200 lines.
(or open the pre-filled issue directly)
← htl HTML 3.0 →