:first-child
Baseline
Widely available
*
This feature is well established and works across many devices and browser versions. It’s been available across browsers since 2015年7月.
* Some parts of this feature may have varying levels of support.
嘗試一下
p {
font-weight: bold;
}
li:first-child {
border: 2px solid orange;
}
<p>田徑冠軍：</p>
<ul>
<li>Adhemar da Silva</li>
<li>Wang Junxia</li>
<li>Wilma Rudolph</li>
<li>Babe Didrikson-Zaharias</li>
<li>Betty Cuthbert</li>
<li>Fanny Blankers-Koen</li>
<li>Florence Griffith-Joyner</li>
<li>Irena Szewinska</li>
<li>Jackie Joyner-Kersee</li>
<li>Shirley Strickland</li>
<li>Carl Lewis</li>
<li>Emil Zatopek</li>
<li>Haile Gebrselassie</li>
<li>Jesse Owens</li>
<li>Jim Thorpe</li>
<li>Paavo Nurmi</li>
<li>Sergei Bubka</li>
<li>Usain Bolt</li>
</ul>
語法
css
:first-child {
/* ... */
}
範例
基本範例
HTML
html
<div>
<p>這段文字被選取了！</p>
<p>這段文字沒有被選取。</p>
</div>
<div>
<h2>這段文字沒有被選取：它不是一個 `p` 元素。</h2>
<p>這段文字沒有被選取。</p>
</div>
CSS
css
p:first-child {
color: lime;
background-color: black;
padding: 5px;
}
結果
為列表設定樣式
HTML
html
<ul>
<li>項目 1</li>
<li>項目 2</li>
<li>
項目 3
<ul>
<li>項目 3.1</li>
<li>項目 3.2</li>
<li>項目 3.3</li>
</ul>
</li>
</ul>
CSS
css
ul li {
color: blue;
}
ul li:first-child {
color: red;
font-weight: bold;
}
結果
規範
| Specification |
|---|
| Selectors Level 4 # first-child-pseudo |
瀏覽器相容性
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