CSS 计数器
CSS 计数器通过一个变量来设置，根据规则递增变量。
使用计数器自动编号
CSS 计数器根据规则来递增变量。
CSS 计数器使用到以下几个属性：
-
counter-reset- 创建或者重置计数器 -
counter-increment- 递增变量 -
content- 插入生成的内容 -
counter()或counters()函数 - 将计数器的值添加到元素
要使用 CSS 计数器，得先用 counter-reset 创建：
以下实例在页面创建一个计数器 (在 body 选择器中)，每个
元素的计数值都会递增，并在每个
元素前添加 "Section 计数值>:"
CSS 实例
body {
counter-reset: section;
}
h2::before {
counter-increment: section;
content: "Section " counter(section) ": ";
}
嵌套计数器
CSS 实例
body {
counter-reset: section;
} h2::before {
counter-increment: section;
content: "Section " counter(section) ": ";
}
counter-reset: section;
} h2::before {
counter-increment: section;
content: "Section " counter(section) ": ";
}
嵌套计数器
以下实例在页面创建一个计数器，在每一个
元素前添加计数值 "Section 主标题计数值>.", 嵌套的计数值则放在
元素的前面，内容为 "主标题计数值>.副标题计数值>":
CSS 实例
body {
counter-reset: section;
}
h1 {
counter-reset: subsection;
}
h1::before {
counter-increment: section;
content: "Section " counter(section) ". ";
}
h2::before {
counter-increment: subsection;
content: counter(section) "." counter(subsection) " ";
}
CSS 实例
body {
counter-reset: section;
} h1 {
counter-reset: subsection;
} h1::before {
counter-increment: section;
content: "Section " counter(section) ". ";
} h2::before {
counter-increment: subsection;
content: counter(section) "." counter(subsection) " ";
}
counter-reset: section;
} h1 {
counter-reset: subsection;
} h1::before {
counter-increment: section;
content: "Section " counter(section) ". ";
} h2::before {
counter-increment: subsection;
content: counter(section) "." counter(subsection) " ";
}
计数器也可用于列表中，列表的子元素会自动创建。这里我们使用了
counters() 函数在不同的嵌套层级中插入字符串:
CSS 实例
ol {
counter-reset: section;
list-style-type: none;
} li::before {
counter-increment: section;
content: counters(section,".") " ";
}
counter-reset: section;
list-style-type: none;
} li::before {
counter-increment: section;
content: counters(section,".") " ";
}
CSS 计数器属性
| 属性 | 描述 |
|---|---|
| content | 使用 ::before 和 ::after 伪元素来插入自动生成的内容 |
| counter-increment | 递增一个或多个值 |
| counter-reset | 创建或重置一个或多个计数器 |
