Run results for: getElementById vs querySelector

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_3_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) GSA/356.2.728375747 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 18

Operating system: iOS 18.3.1

Device Platform: Mobile

Date tested: one year ago

getElementById

20.3M/s

querySelector

2.8M/s

View exact numbers

Test name	Executions per second
✓ getElementById	20,295,050 Ops/sec
querySelector	2,821,253 Ops/sec

HTML Preparation code:

<div id="testElement"></div>

Tests:

getElementById
var el = document.getElementById('testElement'); var className = el.className;
querySelector
var el = document.querySelector('#testElement'); var className = el.className;