Run results for: jQuery by class vs Document.getElementsByClassName

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:76.0) Gecko/20100101 Firefox/76.0

Browser: Firefox 76

Operating system: Mac OS X 10.13

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
jQuery	768049.8 Ops/sec
Vanilla JS	2657758.0 Ops/sec

HTML Preparation code:

<script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.1.0.min.js"></script>
<div id="testElement" class="testClass"></div>
<div id="testElement2" class="testClass"></div>
<div id="testElement3" class="notTestClass"></div>

Tests:

jQuery
var el = $(".testClass")[0]; var className = el.className;
Vanilla JS
var el = document.getElementsByClassName('testClass')[0]; var className = el.className;

Run results for: jQuery by class vs Document.getElementsByClassName

Comparing speed of getting element by id with jQuery vs Vanilla JS

jQuery

Vanilla JS