Syntax
<strong>Important text</strong>
<em>Emphasized text</em>
<mark>Highlighted text</mark>Examples
Semantic Emphasis
Using strong and em for meaningful emphasis within a sentence.
<p>This step is <strong>absolutely required</strong> before continuing, and you should <em>really</em> double-check it.</p>Visual-Only Styling
Using b and i when bold/italic styling is needed without implying importance.
<p>The ship <i>Titanic</i> set sail in 1912. Its name was later used for <b>Titanic</b>, the 1997 film.</p>Highlighting Search Results
Using mark to highlight matched text, and small for a disclaimer.
<p>Results for "closures": JavaScript <mark>closures</mark> let inner functions access outer scope.</p>
<p><small>Prices shown do not include tax.</small></p>Best practices
- Use <strong>/<em> when the emphasis is semantically meaningful; use <b>/<i> for purely visual styling with no added meaning
- Do not use these elements just to make text bold or italic for decoration — prefer CSS font-weight/font-style for pure styling
- Use <mark> sparingly, for content that is genuinely relevant to what the user is currently looking for
- <small> is for fine print and side comments, not for making arbitrary text visually smaller
Browser compatibility
Support applies to the named feature, not every attribute or behaviour in this article. Versions refer to browsers, not operating systems.
<strong>
Desktop
- Chrome
- Supported
From 1 - Firefox
- Supported
From 1 - Safari
- Supported
By 4 (possibly earlier) - Edge
- Supported
From 12 - Opera
- Supported
From 15
Mobile
- Safari on iOS
- Supported
By 3.2 (possibly earlier) - Chrome for Android
- Supported
From 18 - Firefox for Android
- Supported
From 4 - Samsung Internet
- Supported
From 1.0
MDN BCD record for this feature · MDN reference
Support history and limitations
Chrome
- From 1
Firefox
- From 1 · Before Firefox 4, creating a <strong> element incorrectly resulted in an HTMLSpanElement object, instead of the expected HTMLElement.
Safari
- By 4 (possibly earlier)
Edge
- From 12
Opera
- From 15
Safari on iOS
- By 3.2 (possibly earlier)
Chrome for Android
- From 18
Firefox for Android
- From 4
Samsung Internet
- From 1.0
<em>
Desktop
- Chrome
- Supported
From 1 - Firefox
- Supported
From 1 - Safari
- Supported
By 4 (possibly earlier) - Edge
- Supported
From 12 - Opera
- Supported
From 15
Mobile
- Safari on iOS
- Supported
By 3.2 (possibly earlier) - Chrome for Android
- Supported
From 18 - Firefox for Android
- Supported
From 4 - Samsung Internet
- Supported
From 1.0
MDN BCD record for this feature · MDN reference
Support history and limitations
Chrome
- From 1
Firefox
- From 1
Safari
- By 4 (possibly earlier)
Edge
- From 12
Opera
- From 15
Safari on iOS
- By 3.2 (possibly earlier)
Chrome for Android
- From 18
Firefox for Android
- From 4
Samsung Internet
- From 1.0
<b>
Desktop
- Chrome
- Supported
From 1 - Firefox
- Supported
From 1 - Safari
- Supported
From 1 - Edge
- Supported
From 12 - Opera
- Supported
From 15
Mobile
- Safari on iOS
- Supported
From 1 - Chrome for Android
- Supported
From 18 - Firefox for Android
- Supported
From 4 - Samsung Internet
- Supported
From 1.0
MDN BCD record for this feature · MDN reference
Support history and limitations
Chrome
- From 1
Firefox
- From 1 · Before Firefox 4, this element implemented the HTMLSpanElement interface instead of the standard HTMLElement interface.
Safari
- From 1
Edge
- From 12
Opera
- From 15
Safari on iOS
- From 1
Chrome for Android
- From 18
Firefox for Android
- From 4
Samsung Internet
- From 1.0
<i>
Desktop
- Chrome
- Supported
From 1 - Firefox
- Supported
From 1 - Safari
- Supported
From 1 - Edge
- Supported
From 12 - Opera
- Supported
From 15
Mobile
- Safari on iOS
- Supported
From 1 - Chrome for Android
- Supported
From 18 - Firefox for Android
- Supported
From 4 - Samsung Internet
- Supported
From 1.0
MDN BCD record for this feature · MDN reference
Support history and limitations
Chrome
- From 1
Firefox
- From 1
Safari
- From 1
Edge
- From 12
Opera
- From 15
Safari on iOS
- From 1
Chrome for Android
- From 18
Firefox for Android
- From 4
Samsung Internet
- From 1.0
<mark>
Desktop
- Chrome
- Supported
From 7 - Firefox
- Supported
From 4 - Safari
- Supported
From 5.1 - Edge
- Supported
From 12 - Opera
- Supported
From 11
Mobile
- Safari on iOS
- Supported
From 5 - Chrome for Android
- Supported
From 18 - Firefox for Android
- Supported
From 4 - Samsung Internet
- Supported
From 1.0
MDN BCD record for this feature · MDN reference
Support history and limitations
Chrome
- From 7
Firefox
- From 4
Safari
- From 5.1
Edge
- From 12
Opera
- From 11
Safari on iOS
- From 5
Chrome for Android
- From 18
Firefox for Android
- From 4
Samsung Internet
- From 1.0
<small>
Desktop
- Chrome
- Supported
From 1 - Firefox
- Supported
From 1 - Safari
- Supported
By 4 (possibly earlier) - Edge
- Supported
From 12 - Opera
- Supported
From 15
Mobile
- Safari on iOS
- Supported
By 3.2 (possibly earlier) - Chrome for Android
- Supported
From 18 - Firefox for Android
- Supported
From 4 - Samsung Internet
- Supported
From 1.0
MDN BCD record for this feature · MDN reference
Support history and limitations
Chrome
- From 1
Firefox
- From 1
Safari
- By 4 (possibly earlier)
Edge
- From 12
Opera
- From 15
Safari on iOS
- By 3.2 (possibly earlier)
Chrome for Android
- From 18
Firefox for Android
- From 4
Samsung Internet
- From 1.0
MDN BCD 8.1.5 · Dataset built 2026-10-08 · Mapping reviewed 2026-10-21. These dates are not individual browser-test or claim-verification dates. Unknown means the data does not establish support.