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The hierarchical selector is a commonly used selector in CSS, which can select based on the relationship between elements. The following are several commonly used hierarchical selectors and code examples:
The descendant selector is used to select all descendants within the specified element. element. The syntax is: ancestor descendant
.
Example:
<style> /* 选择所有 <div> 元素内的 <p> 元素 */ div p { color: blue; } </style> <div> <p>这是一个段落。</p> <!-- 被选择 --> <span> <p>这是另一个段落。</p> <!-- 被选择 --> </span> </div> <p>这是一个独立的段落。</p> <!-- 不被选择 -->
The child selector is used to select the direct child elements of the specified element. The syntax is: parent > child
.
Example:
<style> /* 选择父元素为 <div> 的直接子元素 <p> */ div > p { color: red; } </style> <div> <p>这是一个段落。</p> <!-- 被选择 --> <span> <p>这是另一个段落。</p> <!-- 不被选择 --> </span> </div>
The sibling selector is used to select the next sibling element of the specified element. Its syntax is: element sibling
.
Example:
<style> /* 选择 <p> 元素下一个兄弟元素 <span> */ p + span { color: green; } </style> <p>这是一个段落。</p> <span>这是一个<span>元素。</span></span> <!-- 被选择 --> <span>这是另一个<span>元素。</span></span> <!-- 不被选择 -->
The adjacent sibling selector is used to select everything after the specified element Bro elements. Its syntax is: element ~ sibling
.
Example:
<style> /* 选择 <p> 元素后的所有兄弟元素 <span> */ p ~ span { font-weight: bold; } </style> <p>这是一个段落。</p> <span>这是一个<span>元素。</span></span> <!-- 被选择 --> <div>这是一个<div>元素。</div></div> <!-- 被选择 --> <span>这是另一个<span>元素。</span></span> <!-- 被选择 -->
Hierarchical selectors are very useful in CSS, allowing for flexible style selection based on the relationship between elements. The above are several common hierarchical selectors and their code examples. I hope they will be helpful to you.
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