Element.querySelector()

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句法
范例
规范
浏览器兼容性
另请参阅
相关话题

querySelector() 方法在 元素 interface returns the first element that is a descendant of the element on which it is invoked that matches the specified group of selectors.

句法

element = baseElement.querySelector(selectors);

参数

selectors: A group of selectors to match the descendant elements of the 元素 baseElement against; this must be valid CSS syntax, or a SyntaxError exception will occur. The first element found which matches this group of selectors is returned.

返回值

The first descendant element of baseElement which matches the specified group of selectors . The entire hierarchy of elements is considered when matching, including those outside the set of elements including baseElement and its descendants; in other words, selectors is first applied to the whole document, not the baseElement , to generate an initial list of potential elements. The resulting elements are then examined to see if they are descendants of baseElement . The first match of those remaining elements is returned by the querySelector() 方法。

If no matches are found, the returned value is null .

异常

SyntaxError: 指定 selectors are invalid.

范例

Let's consider a few examples.

Find a specific element with specific values of an attribute

In this first example, the first <style> element which either has no type or has type "text/css" in the HTML document body is returned:

var el = document.body.querySelector("style[type='text/css'], style:not([type])");

The entire hierarchy counts

This example demonstrates that the hierarchy of the entire document is considered when applying selectors , so that levels outside the specified baseElement are still considered when locating matches.

HTML

<div>
  <h5>Original content</h5>
  <p>
    inside paragraph
    <span>inside span</span>
    inside paragraph
  </p>
</div>
<div>
  <h5>Output</h5>
  <div id="output"></div>
</div>

JavaScript

var baseElement = document.querySelector("p");
document.getElementById("output").innerHTML =
  (baseElement.querySelector("div span").innerHTML);

结果

结果看起来像这样:

Notice how the "div span" selector still successfully matches the <span> element, even though the baseElement 's child nodes do not include the div element (it is still part of the specified selector).

More examples

见 Document.querySelector() for additional examples of the proper format for the selectors .

规范

规范	状态	注释
DOM The definition of 'querySelector()' in that specification.	实时标准
Selectors API Level 2 The definition of 'querySelectorAll()' in that specification.	过时
Selectors API Level 1 The definition of 'querySelectorAll()' in that specification.	过时

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`querySelector`	Chrome 1	Edge 12	Firefox 3.5	IE 9 9 部分支持 8 `querySelector()` is supported, but only for CSS 2.1 selectors.	Opera 10	Safari 3.1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 2	Samsung Internet Android 1.0

图例

完整支持

另请参阅

使用选择器定位 DOM 元素
Attribute selectors in the CSS Guide
Attribute selectors in the MDN Learning Area
Element.querySelectorAll()
Document.querySelector() and Document.querySelectorAll()
DocumentFragment.querySelector() and DocumentFragment.querySelectorAll()
ParentNode.querySelector() and ParentNode.querySelectorAll()
用于 querySelector 的代码片段
Other methods that take selectors: element.closest() and element.matches() .

元数据

最后修改： 2019 年 3 月 23 日

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句法

参数

返回值

异常

范例