Run results for: document.querySelector vs document.body.querySelector vs getElementsByClassName

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.104.5112.20 Safari/537.36 Edg/99.104.1293.14

Browser: Chrome 99

Operating system: Linux

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
querySelector	4926617.0 Ops/sec
querySelector.body	4998641.0 Ops/sec
getElementsByClassName	5815904.0 Ops/sec
getElementsByClassName BODY	5565957.0 Ops/sec

HTML Preparation code:

<div class="testElement"></div>

Tests:

querySelector
var el = document.querySelector('.testElement');
querySelector.body
var el = document.body.querySelector('.testElement');
getElementsByClassName
var el = document.getElementsByClassName('testElement');
getElementsByClassName BODY
var el = document.body.getElementsByClassName('testElement');