The <u> tag renders an underline representing a non-textual annotation — like flagging a misspelled word, or marking a proper name in languages that use underlines for that purpose — not general emphasis or decoration.
Syntax
<u>text to underline</u>Basic Example
<p>Draft note: this paragraph mentions <u>recieve</u> — check spelling before publishing.</p>Browser output: the word "recieve" appears with an underline — the kind of annotation a proofreading or spell-check tool would apply, not a stylistic choice.
How It Works
The browser applies a default underline via CSS. Because underlines are the near-universal visual signal for a clickable link on the web, using <u> on plain text creates a real risk of confusing users into thinking it's a link.
Important Attributes
| Attribute | Purpose |
|---|---|
| — none — | Only universal global attributes apply |
Real-World Example
Spelling and grammar checking tools (like a browser's built-in spellchecker, or a writing-assistant UI) commonly use an underline specifically to flag words needing review — a legitimate, narrow use of this annotation pattern.
Common Mistakes
- Underlining text purely for decoration or emphasis — readers will very likely assume it's a broken or unstyled link
- Using
<u>as a shortcut for CSStext-decoration: underlineon headings or titles where no annotation meaning is intended
Best Practices
- Avoid underlining plain text for style — reserve underlines visually for links, and reserve
<u>semantically for genuine non-textual annotation - For emphasis, use
<em>or<strong>; for pure decoration, use CSS deliberately on a non-link element and be sure the context makes clear it isn't a link
Accessibility Considerations
Underlined non-link text can mislead users who rely on visual patterns to identify interactive elements, including some users with cognitive or visual processing differences who scan pages for underlines specifically to find links.
SEO Considerations
No direct ranking effect.
Browser & Modern HTML Notes
<u> is valid in HTML5 with this redefined annotation meaning, but it's one of the least-used inline text tags in modern web design specifically because of the link-confusion problem — most designs avoid it entirely.
Mini Practice
- Mark a misspelled word in a sample paragraph using
<u>the way a spellchecker would. - Find an example (real or hypothetical) of
<u>being misused for decoration, and rewrite it using the correct tag instead.
