Run results for: Get elements by class: jQuery vs querySelectorAll

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.117 Safari/537.36

Browser: Chrome 79

Operating system: Windows

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
jQuery	423222.0 Ops/sec
querySelectorAll	996518.3 Ops/sec
getElementsByClassName	5580053.0 Ops/sec
jQuery mixed selector	228895.0 Ops/sec
querySelectorAll mixed selector	726108.9 Ops/sec

HTML Preparation code:

<ul id="theList">
  <li class="odd">Item 1</li>    
  <li class="even">Item 2</li>    
  <li class="odd">Item 3</li>    
  <li class="even">Item 4</li>    
  <li class="odd">Item 5</li>    
  <li class="even">Item 6</li>    
  <li class="odd">Item 7</li>    
  <li class="even">Item 8</li>    
  <li class="odd">Item 9</li>    
  <li class="even">Item 10</li>    
  <li class="odd">Item 11</li>    
  <li class="even">Item 12</li>    
  <li class="odd">Item 13</li>    
  <li class="even">Item 14</li>    
  <li class="odd">Item 15</li>    
  <li class="even">Item 16</li>    
  <li class="odd">Item 17</li>    
  <li class="even">Item 18</li>    
  <li class="odd">Item 19</li>    
  <li class="even">Item 20</li>    
  <li class="odd">Item 21</li>    
  <li class="even">Item 22</li>    
  <li class="odd">Item 23</li>    
  <li class="even">Item 24</li>    
  <li class="odd">Item 25</li>    
  <li class="even">Item 26</li>    
  <li class="odd">Item 27</li>    
  <li class="even">Item 28</li>    
  <li class="odd">Item 29</li>    
  <li class="even">Item 30</li>    
</ul>

<script src='https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js'></script>

Tests:

jQuery
var els = $('.even');
querySelectorAll
var els = document.querySelectorAll('.even');
getElementsByClassName
var els = document.getElementsByClassName('even');
jQuery mixed selector
var els = $('li.even');
querySelectorAll mixed selector
var els = document.querySelectorAll('li.even');

Run results for: Get elements by class: jQuery vs querySelectorAll

Compare various methods of obtaining a group of elements identified by class name

jQuery

querySelectorAll

getElementsByClassName

jQuery mixed selector

querySelectorAll mixed selector