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/131.0.0.0 Safari/537.36

Browser: Chrome 131

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Benchmark engine: Benchmark.js

getElementsByClassName

16.8M/s

getElementsByClassName BODY

13.5M/s

querySelector.body

13.2M/s

querySelector

13.1M/s

View exact numbers

Test name	Executions per second
✓ getElementsByClassName	16,831,302 Ops/sec
getElementsByClassName BODY	13,542,895 Ops/sec
querySelector.body	13,190,358 Ops/sec
querySelector	13,135,624 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');