类选择器

该 CSS 类选择器根据其 class 属性的内容匹配元素。

css
/* All elements with class="spacious" */
.spacious {
  margin: 2em;
}

/* All <li> elements with class="spacious" */
li.spacious {
  margin: 2em;
}

/* All <li> elements with a class list that includes both "spacious" and "elegant" */
/* For example, class="elegant retro spacious" */
li.spacious.elegant {
  margin: 2em;
}

语法

css
.class_name { style properties }

请注意，这等效于以下 属性选择器

css
[class~=class_name] { style properties }

class_name 值必须是有效的 CSS 标识符。不是有效 CSS 标识符的 HTML class 属性必须在用作类选择器之前进行 转义。

示例

有效的类选择器

HTML

html
<p class="red">This paragraph has red text.</p>
<p class="red yellow-bg">
  This paragraph has red text and a yellow background.
</p>
<p class="red fancy">This paragraph has red text and "fancy" styling.</p>
<p>This is just a regular paragraph.</p>
html
<!-- The next two paragraphs have class attributes
that contain characters which must be escaped in CSS -->

<p class="item?one">This paragraph has a pink background.</p>
<p class="123item">This paragraph has a yellow background.</p>

CSS

css
.red {
  color: #f33;
}

.yellow-bg {
  background: #ffa;
}

.fancy {
  font-weight: bold;
  text-shadow: 4px 4px 3px #77f;
}
css
/* In the next two rules, the class attributes must be escaped */

.item\?one {
  background-color: pink;
}

.\00003123item {
  background-color: yellow;
}

结果

无效的类选择器

以下规则中的类选择器不是有效的 CSS 标识符，将被忽略。

css
.item?one {
  background-color: green;
}

.123item {
  background-color: green;
}

规范

规范
选择器级别 4
# class-html

浏览器兼容性

BCD 表格仅在浏览器中加载

另请参阅