Element.querySelectorAll()

Summary

Gibt eine statische NodeList aller Elemente absteigend des Elements, auf welchem querySelectorAll ausgeführt wird, die mit den angegebenen CSS Selektoren übereinstimmen.

Syntax

elementList = baseElement.querySelectorAll(selectors);

wobei:

elementList

ist statische Node Liste [ NodeList[elements] ] mit element Objekten.

baseElement

ist ein element Objekt.

selectors

ist eine Gruppe von Selektoren die mit dem Element im DOM übereinstimmen soll. 

Beispiele

Dieses Beispiel gibt eine Liste aller p Elementen im HTML body zurück:

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"

This example returns a list of iframe elements that contain a data attribute 'src':

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

Bemerkungen

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 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

Specifications

Browser compatibility

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

See also

• querySelector()
• document.querySelectorAll
• document.querySelector
• Code snippets for querySelector