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

Run details:

User agent: Mozilla/5.0 (X11; CrOS x86_64 14541.0.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser: Chrome 120

Operating system: Chrome OS 14541.0.0

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
querySelector	7928498.5 Ops/sec
querySelector.body	8452533.0 Ops/sec
getElementsByClassName	9482571.0 Ops/sec
getElementsByClassName BODY	8166559.5 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');