Run results for: getElementById vs querySelector

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 12_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/16A366 [FBAN/MessengerForiOS;FBAV/206.0.0.53.105;FBBV/145487838;FBDV/iPhone8,2;FBMD/iPhone;FBSN/iOS;FBSV/12.0;FBSS/3;FBCR/Carrier;FBID/phone;FBLC/en_GB;FBOP/5]

Browser: Mobile Safari 12

Operating system: iOS 12.0

Device Platform: Mobile

Date tested: 5 years ago

Test name	Executions per second
getElementById	1008749.0 Ops/sec
querySelector	819342.4 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;