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

Run details:

User agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.181 Safari/537.36

Browser: Chrome 66

Operating system: Windows 7

Device Platform: Other

Date tested: 6 years ago

Test name	Executions per second
jQuery	320069.2 Ops/sec
querySelectorAll	61764.3 Ops/sec
getElementsByClassName	2749203.5 Ops/sec
jQuery: mixed selector	47755.9 Ops/sec
querySelectorAll: mixed selector	57745.8 Ops/sec
with Id	545648.7 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>

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');
with Id
var els = document.getElementById("theList").querySelectorAll('.even');

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

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

jQuery

querySelectorAll

getElementsByClassName

jQuery: mixed selector

querySelectorAll: mixed selector

with Id