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/135.0.0.0 Safari/537.36 Edg/135.0.0.0

Browser: Chrome 135

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Benchmark engine: Benchmark.js

getElementsByClassName

18.5M/s

querySelector.body

15.3M/s

getElementsByClassName BODY

14.6M/s

querySelector

13.6M/s

View exact numbers

Test name	Executions per second
✓ getElementsByClassName	18,459,414 Ops/sec
querySelector.body	15,292,803 Ops/sec
getElementsByClassName BODY	14,552,429 Ops/sec
querySelector	13,568,767 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');