：
方法一：通用兄弟選取器（ ~ ）
<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Document</title> <meta name="viewport" content="width=device-width"> <style> ul {margin: 0; padding: 0;} li { list-style: none; height: 50px; line-height: 50px;} li~li {border-top: 1px solid #000;} </style></head><body> <ul> <li>1</li> <li>2</li> <li>3</li> <li>4</li> <li>5</li> <li>6</li> </ul></body></html>
li~li {...} 中的 ~ 符號稱為通用兄弟選取器，匹配P元素之後的P元素，所以第一個P元素不會匹配到。
方法二：偽類別選取器（ :first-of-type / :last-of-type ）
<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Document</title> <meta name="viewport" content="width=device-width"> <style> ul {margin: 0; padding: 0;} li { border-top: 1px solid #000; list-style: none; height: 50px; line-height: 50px;} li:first-of-type {border-top: none;} </style></head><body> <ul> <li>1</li> <li>2</li> <li>3</li> <li>4</li> <li>5</li> <li>6</li> </ul></body></html>
首先將所有 li 設定 border-top，然後用 :first-of-type 尋找到第一個 li ，取消border-top。
相信看了本文案例你已經掌握了方法，更多精彩請關注php中文網其它相關文章！
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