HTML <u> tag
The <u> tag is used to underline text.
NOTE: The <u> tag is deprecated and will not work with the XHTML Strict document type.
Standard attributes
class, dir, id, lang, style, title, xml:lang
For more information on standard attributes, check out our HTML standard attributes reference page.
Event attributes
onclick, ondblclick, onmousedown, onmousemove, onmouseout, onmouseover, onmouseup, onkeydown, onkeypress, onkeyup
For more information on event attributes, check out our HTML event attributes reference page.
Example
Tips & notes
Web users are used to associating underlined text with links so only links should be underlined on a page. Try not to use the <u> tag unless you really need to emphasize some text, and if that's the case consider another way to emphasize text like making text bold or italic.
It's better to use CSS to style text than text formatting tags like <u>.