Document.querySelectorAll()
  The Document method querySelectorAll()
  returns a static (not live) NodeList representing a list of the
  document's elements that match the specified group of selectors.
Syntax
elementList = parentNode.querySelectorAll(selectors);
Parameters
selectors- 
    
A
DOMStringcontaining one or more selectors to match against. This string must be a valid CSS selector string; if it's not, aSyntaxErrorexception is thrown. See Locating DOM elements using selectors for more information about using selectors to identify elements. Multiple selectors may be specified by separating them using commas. 
Note: Characters which are not part of standard CSS syntax must be escaped using a backslash character. Since JavaScript also uses backslash escaping, special care must be taken when writing string literals using these characters. See Escaping special characters for more information.
Return value
  A non-live NodeList containing one Element object for
  each element that matches at least one of the specified selectors or an empty
  NodeList in case of no matches.
    Note: If the specified selectors include a CSS pseudo-element, the returned list
    is always empty.
  
Exceptions
SyntaxError- 
    
The syntax of the specified
selectorsstring is not valid. 
Examples
Obtaining a list of matches
  To obtain a NodeList of all of the <p> elements in the
  document:
const matches = document.querySelectorAll("p");
  This example returns a list of all <div> elements within the document
  with a class of either note or alert:
const matches = document.querySelectorAll("div.note, div.alert");
  Here, we get a list of <p> elements whose immediate parent element
  is a <div> with the class highlighted and which are
  located inside a container whose ID is test.
const container = document.querySelector("#test");
const matches = container.querySelectorAll("div.highlighted > p");
  This example uses an attribute
selector to return a list of the <iframe> elements in the
  document that contain an attribute named data-src:
const matches = document.querySelectorAll("iframe[data-src]");
  Here, an attribute selector is used to return a list of the list items contained within
  a list whose ID is userlist which have a data-active attribute
  whose value is 1:
const container = document.querySelector("#userlist");
const matches = container.querySelectorAll("li[data-active='1']");
Accessing the matches
  Once the NodeList of matching elements is returned, you can examine it
  just like any array. If the array is empty (that is, its length property is
  0), then no matches were found.
Otherwise, you can use standard array notation to access the contents of the list. You can use any common looping statement, such as:
const highlightedItems = userList.querySelectorAll(".highlighted");
highlightedItems.forEach(function(userItem) {
  deleteUser(userItem);
});
User notes
  querySelectorAll() behaves differently than most common JavaScript DOM
  libraries, which might lead to unexpected results.
HTML
Consider this HTML, with its three nested <div> blocks.
<div class="outer">
  <div class="select">
    <div class="inner">
    </div>
  </div>
</div>
JavaScript
const select = document.querySelector('.select');
const inner = select.querySelectorAll('.outer .inner');
inner.length; // 1, not 0!
  In this example, when selecting .outer .inner in the context of the
  <div> with the class select, the element with the class
  .inner is still found, even though .outer is not a descendant
  of the base element on which the search is performed (.select). By default,
  querySelectorAll() only verifies that the last element in the selector is
  within the search scope.
  The :scope pseudo-class restores the expected behavior, only matching
  selectors on descendants of the base element:
const select = document.querySelector('.select');
const inner = select.querySelectorAll(':scope .outer .inner');
inner.length; // 0
Specifications
| Specification | 
|---|
| DOM Standard  # ref-for-dom-parentnode-queryselectorall①  | 
Browser compatibility
BCD tables only load in the browser
See also
- Locating DOM elements using selectors
 - Attribute selectors in the CSS Guide
 - Attribute selectors in the MDN Learning Area
 Element.querySelector()andElement.querySelectorAll()Document.querySelector()- 
    
DocumentFragment.querySelector()andDocumentFragment.querySelectorAll()