Run results for: className vs setAttribute vs classList

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 12_4 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15E148 Instagram 106.0.0.9.118 (iPhone10,6; iOS 12_4; en_GB; en-GB; scale=3.00; 1125x2436; 166752244)

Browser: Mobile Safari 12

Operating system: iOS 12.4

Device Platform: Mobile

Date tested: 4 years ago

Test name	Executions per second
className	8396.5 Ops/sec
setAttribute	6765.4 Ops/sec
classList	5548.8 Ops/sec

HTML Preparation code:

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

Script Preparation code:

var element = document.getElementById('foo');

Tests:

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