Run results for: getElementById vs querySelector ID vs getElementsByClassName vs querySelectorAll

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/122.0.6261.89 Mobile/15E148 Safari/604.1

Browser: Chrome Mobile iOS 122

Operating system: iOS 17.3

Device Platform: Mobile

Date tested: 2 years ago

getElementById

7.7M/s

getElementsByClassName

6.6M/s

querySelector class

4.1M/s

querySelector

3.5M/s

querySelectorAll

2.8M/s

View exact numbers

Test name	Executions per second
✓ getElementById	7,738,753 Ops/sec
getElementsByClassName	6,595,062 Ops/sec
querySelector class	4,069,143 Ops/sec
querySelector	3,510,498 Ops/sec
querySelectorAll	2,778,360 Ops/sec

HTML Preparation code:

<div id="test_element_id" class="test_element_class"></div>

Tests:

getElementById
var el = document.getElementById('test_element_id'); var className = el.className;
querySelector
var el = document.querySelector('#test_element_id'); var className = el.className;
getElementsByClassName
var el = document.getElementsByClassName('test_element_class')[0]; var className = el.className;
querySelectorAll
var el = document.querySelectorAll('.test_element_class')[0]; var className = el.className;
querySelector class
var el = document.querySelector('.test_element_class'); var className = el.className;