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: 8 months ago

Test name	Executions per second
getElementById	7722356.5 Ops/sec
querySelector	3465446.2 Ops/sec
getElementsByClassName	6610380.0 Ops/sec
querySelectorAll	2745637.5 Ops/sec
querySelector class	4065802.0 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;

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

getElementById

querySelector

getElementsByClassName

querySelectorAll

querySelector class