Run results for: parent vs document queryselectorAll

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Safari/537.36

Browser: Chrome 106

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
parent.querySelector	984672.4 Ops/sec
document.querySelector	468034.7 Ops/sec
document.querySelector 2	904307.8 Ops/sec

HTML Preparation code:

<div id="main">
<div><div><div><div><div><div>
  
<div id="parent">
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
  <div class="child"></div>
</div>

</div></div></div></div></div></div>
</div>

Script Preparation code:

var main = document.querySelector('#main');
var parent = document.querySelector('#parent');

Tests:

parent.querySelector
var child = parent.querySelectorAll('.child');
document.querySelector
var child = main.querySelectorAll('#parent .child');
document.querySelector 2
var child = main.querySelectorAll('.child');

Run results for: parent vs document queryselectorAll

parent.querySelector

document.querySelector

document.querySelector 2