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

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Browser: Chrome 126

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Benchmark engine: Benchmark.js

getElementsByClassName

4.2M/s

querySelector

4.0M/s

querySelector.body

3.8M/s

getElementsByClassName BODY

3.7M/s

View exact numbers

Test name	Executions per second
✓ getElementsByClassName	4,193,580 Ops/sec
querySelector	3,997,627 Ops/sec
querySelector.body	3,783,020 Ops/sec
getElementsByClassName BODY	3,690,636 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');