38 lines
1.0 KiB
Markdown
38 lines
1.0 KiB
Markdown
|
---
|
|||
|
|
title: HTML DOM querySelector()
|
|||
|
|
localeTitle: HTML DOM querySelector（）
|
|||
|
|
---
|
|||
|
|
Document方法`querySelector()`返回文档中与指定选择器或选择器组匹配的`first` Element。如果未找到匹配项，则返回null。
|
|||
|
|
|
|||
|
|
**HTML内容：**
|
|||
|
|
|
|||
|
|
```html
|
|||
|
|
|
|||
|
|
<div id="id-example"></div>
|
|||
|
|
<div class="class-example"></div>
|
|||
|
|
<a>element-example</a>
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
**JavaScript内容：**
|
|||
|
|
|
|||
|
|
```javascript
|
|||
|
|
document.querySelector("#id-example"); // Returns the element with id "id-example"
|
|||
|
|
document.querySelector(".class-example"); // Returns the element with class "class-example"
|
|||
|
|
document.querySelector("a"); // Returns the "a" element
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
注意`querySelector()`返回第一个匹配元素，返回所有匹配项，改为使用querySelectorAll（）方法。
|
|||
|
|
|
|||
|
|
```html
|
|||
|
|
|
|||
|
|
<div id="example">First</div>
|
|||
|
|
<div id="example">Second</div>
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
```javascript
|
|||
|
|
document.querySelector("#example"); // Returns only the element containing 'First'
|
|||
|
|
```
|
|||
|
|
|
|||
|
|
#### 更多信息：
|
|||
|
|
|
|||
|
|
[MDN - document.querySelector（）](https://developer.mozilla.org/en-US/docs/Web/API/Document/querySelector)
|