htmlhint · coliff · Jun 17, 2025 · Jun 17, 2025 · Jun 17, 2025
@@ -38,6 +38,7 @@
     "msapplication",
     "nocolor",
     "nodir",
+    "noembed",
     "nomix",
     "noopener",
     "npmjs",

@@ -33,6 +33,7 @@ export { default as spaceTabMixedDisabled } from './space-tab-mixed-disabled'
 export { default as specCharEscape } from './spec-char-escape'
 export { default as srcNotEmpty } from './src-not-empty'
 export { default as styleDisabled } from './style-disabled'
+export { default as tagNoObsolete } from './tag-no-obsolete'
 export { default as tagnameLowercase } from './tagname-lowercase'
 export { default as tagnameSpecialChars } from './tagname-specialchars'
 export { default as tagPair } from './tag-pair'

@@ -0,0 +1,53 @@
+import { Rule } from '../types'
+
+// List of obsolete HTML5 tags
+const OBSOLETE_TAGS = [
+  'applet',
+  'acronym',
+  'bgsound',
+  'dir',
+  'frame',
+  'frameset',
+  'noframes',
+  'isindex',
+  'keygen',
+  'listing',
+  'menuitem',
+  'nextid',
+  'noembed',
+  'plaintext',
+  'rb',
+  'rtc',
+  'strike',
+  'xmp',
+  'basefont',
+  'big',
+  'blink',
+  'center',
+  'font',
+  'marquee',
+  'multicol',
+  'nobr',
+  'spacer',
+  'tt',
+]
+
+export default {
+  id: 'tag-no-obsolete',
+  description: 'Disallows the use of obsolete HTML5 tags.',
+  init(parser, reporter, _options) {
+    parser.addListener('tagstart,tagend', (event) => {
+      const tagName = event.tagName.toLowerCase()
+
+      if (OBSOLETE_TAGS.includes(tagName)) {
+        reporter.error(
+          `The tag [ ${event.tagName} ] is obsolete in HTML5 and should not be used.`,
+          event.line,
+          event.col,
+          this,
+          event.raw
+        )
+      }
+    })
+  },
+} as Rule
@@ -51,6 +51,7 @@ export interface Ruleset {
   'spec-char-escape'?: boolean
   'src-not-empty'?: boolean
   'style-disabled'?: boolean
+  'tag-no-obsolete'?: boolean
   'tag-pair'?: boolean
   'tag-self-close'?: boolean
   'tagname-lowercase'?: boolean

@@ -0,0 +1,36 @@
+const HTMLHint = require('../../dist/htmlhint.js').HTMLHint
+
+const ruleId = 'tag-no-obsolete'
+const ruleOptions = {}
+
+ruleOptions[ruleId] = true
+
+describe(`Rules: ${ruleId}`, () => {
+  it('Obsolete HTML5 tags should result in an error', () => {
+    const code =
+      '<center>Centered text</center><font color="red">Red text</font><marquee>Scrolling text</marquee>'
+    const messages = HTMLHint.verify(code, ruleOptions)
+    expect(messages.length).toBe(6) // 3 opening tags + 3 closing tags
+    messages.forEach((msg) => expect(msg.rule.id).toBe(ruleId))
+  })
+
+  it('Non-obsolete HTML5 tags should not result in an error', () => {
+    const code = '<div>Content</div><span>Text</span><p>Paragraph</p>'
+    const messages = HTMLHint.verify(code, ruleOptions)
+    expect(messages.length).toBe(0)
+  })
+
+  it('Mixed case obsolete tags should still be detected', () => {
+    const code = '<CENTER>Centered</CENTER><Font>Styled</Font>'
+    const messages = HTMLHint.verify(code, ruleOptions)
+    expect(messages.length).toBe(4) // 2 opening tags + 2 closing tags
+    messages.forEach((msg) => expect(msg.rule.id).toBe(ruleId))
+  })
+
+  it('Self-closing obsolete tags should be detected', () => {
+    const code = '<br><hr><img src="test.jpg"><spacer>'
+    const messages = HTMLHint.verify(code, ruleOptions)
+    expect(messages.length).toBe(1) // Only spacer is obsolete
+    messages.forEach((msg) => expect(msg.rule.id).toBe(ruleId))
+  })
+})
@@ -41,6 +41,7 @@ description: A complete list of all the rules for HTMLHint
 - [`href-abs-or-rel`](href-abs-or-rel/): An href attribute must be either absolute or relative.
 - [`main-require`](main-require/): A document must have at least one `<main>` element in the `<body>` tag.
 - [`src-not-empty`](src-not-empty/): The src attribute of an img(script,link) must have a value.
+  {/* - [`tag-no-obsolete`](tag-no-obsolete/): Disallows the use of obsolete HTML5 tags. */}
 - [`tag-pair`](tag-pair/): Tag must be paired.
 - [`tag-self-close`](tag-self-close/): Empty tags must be self closed.
 - [`tagname-lowercase`](tagname-lowercase/): All HTML element names must be in lowercase.

@@ -0,0 +1,46 @@
+---
+id: tag-no-obsolete
+title: tag-no-obsolete
+description: Disallows the use of obsolete HTML5 tags that are no longer supported in modern browsers.
+sidebar:
+  badge: New
+hidden: true
+---
+
+import { Badge } from '@astrojs/starlight/components';
+
+Disallows the use of obsolete HTML5 tags.
+
+Level: <Badge text="Error" variant="danger" />
+
+## Config value
+
+- `true`: enable rule
+- `false`: disable rule
+
+## Description
+
+This rule prevents the use of HTML tags that have been deprecated and are considered obsolete in HTML5. These tags are no longer supported by modern browsers and should be replaced with appropriate alternatives.
+
+### Obsolete tags include:
+
+- `applet`, `acronym`, `bgsound`, `dir`, `frame`, `frameset`, `noframes`
+- `isindex`, `keygen`, `listing`, `menuitem`, `nextid`, `noembed`
+- `plaintext`, `rb`, `rtc`, `strike`, `xmp`, `basefont`, `big`
+- `blink`, `center`, `font`, `marquee`, `multicol`, `nobr`, `spacer`, `tt`
+
+### The following patterns are **not** considered rule violations
+
+```html
+<div>Content</div>
+<span>Text</span>
+<p>Paragraph</p>
+```
+
+### The following patterns are considered rule violations:
+
+```html
+<center>Centered text</center>
+<font color="red">Red text</font>
+<marquee>Scrolling text</marquee>
+```