Run results for: className vs. setAttribute vs. classList

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 15_7 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/120.0.6099.119 Mobile/15E148 Safari/604.1

Browser: Chrome Mobile iOS 120

Operating system: iOS 15.7

Device Platform: Mobile

Date tested: 2 years ago

className

35K/s

setAttribute

21K/s

classList

12K/s

View exact numbers

Test name	Executions per second
✓ className	34,781 Ops/sec
setAttribute	21,038 Ops/sec
classList	11,615 Ops/sec

HTML Preparation code:

<div id="foo"></div>

Tests:

className
var element = document.getElementById("foo"); var i = 1000; while (i--) { element.className = "bar"; }
setAttribute
var element = document.getElementById("foo"); var i = 1000; while (i--) { element.setAttribute("class", "bar"); }
classList
var element = document.getElementById("foo"); var i = 1000; while (i--) { element.classList.add("bar"); }