<u>:未铰接的注释（下划线）元素
<u> HTML 元素表示一段内联文本，应以指示其具有非文本注释的方式呈现。默认情况下呈现为简单的实线下划线，但可以使用 CSS 进行更改。
¥The <u> HTML element represents a span of inline text which should be rendered in a way that indicates that it has a non-textual annotation. This is rendered by default as a simple solid underline, but may be altered using CSS.
警告：该元素在旧版本的 HTML 中曾被称为 "强调" 元素，并且有时仍会以这种方式被误用。要为文本添加下划线，你应该应用包含设置为
underline的 CSStext-decoration属性的样式。¥Warning: This element used to be called the "Underline" element in older versions of HTML, and is still sometimes misused in this way. To underline text, you should instead apply a style that includes the CSS
text-decorationproperty set tounderline.
Try it
有关何时适合使用 <u>、何时不适合的更多详细信息，请参阅 使用说明 部分。
¥See the Usage notes section for further details on when it's appropriate to use <u> and when it isn't.
属性
使用说明
¥Usage notes
与其他纯样式元素一起，原始 HTML 下划线 (<u>) 元素在 HTML 4 中已被弃用；然而，<u> 在 HTML 5 中被恢复，并具有新的语义含义：将文本标记为应用了某种形式的非文本注释。
¥Along with other pure styling elements, the original HTML Underline (<u>) element was deprecated in HTML 4; however, <u> was restored in HTML 5 with a new, semantic, meaning: to mark text as having some form of non-textual annotation applied.
注意：避免将
<u>元素与其默认样式（带下划线的文本）一起使用，以免与超链接混淆，默认情况下超链接也带有下划线。¥Note: Avoid using the
<u>element with its default styling (of underlined text) in such a way as to be confused with a hyperlink, which is also underlined by default.
用例
¥Use cases
<u> 元素的有效用例包括注释拼写错误、应用 专有名称标记 来表示中文文本中的专有名称以及其他形式的注释。
¥Valid use cases for the <u> element include annotating spelling errors, applying a proper name mark to denote proper names in Chinese text, and other forms of annotation.
你不应使用 <u> 为演示目的的文本下划线，或表示书名。
¥You should not use <u> to underline text for presentation purposes, or to denote titles of books.
需要考虑使用的其他元素
¥Other elements to consider using
在大多数情况下，你应该使用 <u> 以外的元素，例如：
¥In most cases, you should use an element other than <u>, such as:
<em>表示重音强调<b>引起对文本的注意<mark>标记关键词或短语<strong>表示文本具有很强的重要性<cite>标记书籍或其他发布物的标题<i>表示西方文本中的技术术语、音译、思想或船只名称
要提供文本注释（与使用 <u> 创建的非文本注释相反），请使用 <ruby> 元素。
¥To provide textual annotations (as opposed to the non-textual annotations created with <u>), use the <ruby> element.
要应用没有任何语义意义的下划线外观，请使用 text-decoration 属性的值 underline。
¥To apply an underlined appearance without any semantic meaning, use the text-decoration property's value underline.
示例
指示拼写错误
¥Indicating a spelling error
此示例使用 <u> 元素和一些 CSS 来显示包含拼写错误的段落，该错误以红色波浪下划线样式指示，该样式相当常用于此目的。
¥This example uses the <u> element and some CSS to display a paragraph which includes a misspelled error, with the error indicated in the red wavy underline style which is fairly commonly used for this purpose.
HTML
<p>This paragraph includes a <u class="spelling">wrnogly</u> spelled word.</p>
在 HTML 中，我们看到 <u> 与类 spelling 一起使用，该类用于指示单词 "wrongly" 的拼写错误。
¥In the HTML, we see the use of <u> with a class, spelling, which is used to indicate the misspelling of the word "wrongly".
CSS
u.spelling {
text-decoration: red wavy underline;
}
此 CSS 指示当 <u> 元素使用 spelling 类设置样式时，它的文本下方应有一条红色波浪下划线。这是拼写错误的常见样式。另一种常见的风格可以使用 red dashed underline 来呈现。
¥This CSS indicates that when the <u> element is styled with the class spelling, it should have a red wavy underline underneath its text. This is a common styling for spelling errors. Another common style can be presented using red dashed underline.
结果
¥Result
对于任何使用过当今更流行的文字处理器的人来说，结果应该很熟悉。
¥The result should be familiar to anyone who has used any of the more popular word processors available today.
避免 <u>
¥Avoiding <u>
大多数时候，你实际上并不想使用 <u>。以下是一些示例，展示了在几种情况下你应该做什么。
¥Most of the time, you actually don't want to use <u>. Here are some examples that show what you should do instead in several cases.
非语义下划线
¥Non-semantic underlines
要为文本添加下划线而不暗示任何语义，请使用 <span> 元素，并将 text-decoration 属性设置为 "underline"，如下所示。
¥To underline text without implying any semantic meaning, use a <span> element with the text-decoration property set to "underline", as shown below.
HTML
<span class="underline">Today's Special</span>
<br />
Chicken Noodle Soup With Carrots
CSS
.underline {
text-decoration: underline;
}
结果
¥Result
提出书名
¥Presenting a book title
书名应使用 <cite> 元素而不是 <u> 甚至 <i> 来表示。
¥Book titles should be presented using the <cite> element instead of <u> or even <i>.
使用 cite 元素
¥Using the cite element
<p>The class read <cite>Moby Dick</cite> in the first term.</p>
设置 cite 元素的样式
¥Styling the cite element
<cite> 元素的默认样式以斜体呈现文本。你可以使用 CSS 覆盖它：
¥The default styling for the <cite> element renders the text in italics. You can override that using CSS:
<p>The class read <cite>Moby Dick</cite> in the first term.</p>
cite {
font-style: normal;
text-decoration: underline;
}
技术总结
规范
| Specification |
|---|
| HTML Standard # the-u-element |
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