--- title: Element.querySelectorAll() slug: Web/API/Element/querySelectorAll translation_of: Web/API/Element/querySelectorAll ---
{{APIRef("DOM")}}

總覽

Returns a non-live NodeList of all elements descended from the element on which it is invoked that matches the specified group of CSS selectors. (The base element itself is not included, even if it matches.)

表達式

elementList = baseElement.querySelectorAll(selectors);
elementList
is a non-live node list [ NodeList[elements] ] of element objects.
baseElement
is an element object.
selectors
is a group of selectors to match on or elements of the DOM. 

範例

下例是從整個網頁的 body 中，取得所有 p 元素：

let matches = document.body.querySelectorAll('p');

This example returns a list of p children elements under a container, whose parent is a div that has the class 'highlighted':

let el = document.querySelector('#test');    //return an element with id='test'
let matches = el.querySelectorAll('div.highlighted > p'); // return a NodeList of p wrapped in a div with attribute class "highlighted"

下例是取得所有有 attribute data-src 的 iframe 元素：

let matches = el.querySelectorAll('iframe[data-src]');

註

If the specified “selectors” are not found inside the DOM of the page, the method queryselectorAll returns an empty NodeList as specified below:

> let x = document.body.querySelectorAll('.highlighted'); //case: if the class highlighted doesn't exist in any attribute "class" of the DOM the result is
> [] //empty NodeList

querySelectorAll() was introduced in the WebApps API.

The string argument pass to querySelectorAll must follow the CSS syntax. See {{domxref("document.querySelector")}} for a concrete example.

We could access a single item inside the NodeList in the following way:

let x = document.body.querySelectorAll('.highlighted');
x.length; //return the size of x
x[i_item]; //where i_item has a value between 0 and x.length-1. The operator "[]" return as in an array the element at index "i_item"

We could iterate inside a NodeList with the construct for(....) {...} as in the following code:

 let x = document.body.querySelectorAll('.highlighted');
 let index = 0;
 for( index=0; index < x.length; index++ ) {
       console.log(x[index]);
 }

So in the above way, it is possible to manage and modify the behaviour of the page.

Quirks

querySelectorAll() behaves differently than most common JavaScript DOM libraries, which might lead to unexpected results:

<div class="outer">
  <div class="select">
    <div class="inner">
    </div>
  </div>
</div>
let select = document.querySelector('.select');
let inner = select.querySelectorAll('.outer .inner');
inner.length; // 1, not 0!

In this example, when selecting .outer .inner in the context of .select, .inner is still found, even though .outer is not a descendant of the baseElement (.select).
querySelectorAll() only verifies that the last element in the selector is within the baseElement.

The :scope pseudo-class restores the expected behavior, only matching selectors on descendants of the baseElement:

let select = document.querySelector('.select');
let inner = select.querySelectorAll(':scope .outer .inner');
inner.length; // 0

規範

規範 狀態 評論
{{SpecName('DOM4','#dom-parentnode-queryselectorallselectors','querySelectorAll')}} {{Spec2('DOM4')}}  
{{SpecName('Selectors API Level 2','#queryselectorall','querySelectorAll')}} {{Spec2('Selectors API Level 2')}}  
{{SpecName('Selectors API Level 1','#queryselectorall','querySelectorAll')}} {{Spec2('Selectors API Level 1')}}  

瀏覽器相容性

{{Compat("api.Element.querySelectorAll")}}

[1] Supported in Opera 15+ by enabling the "Enable <style scoped>" or "Enable experimental Web Platform features" flag in chrome://flags.

參見