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

Benchmark engine: Benchmark.js

getElementsByClassName

9.5M/s

querySelector.body

8.5M/s

getElementsByClassName BODY

8.2M/s

querySelector

7.9M/s

View exact numbers

Test name	Executions per second
✓ getElementsByClassName	9,482,571 Ops/sec
querySelector.body	8,452,533 Ops/sec
getElementsByClassName BODY	8,166,560 Ops/sec
querySelector	7,928,498 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');