Run results for: className vs. setAttribute vs. classList

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 11_2_2 like Mac OS X) AppleWebKit/604.1.34 (KHTML, like Gecko) CriOS/64.0.3282.112 Mobile/15C202 Safari/604.1

Browser: Chrome Mobile iOS 64

Operating system: iOS 11.2.2

Device Platform: iPhone

Date tested: 2024 years ago

Test name	Executions per second
className	17196.4 Ops/sec
setAttribute	9386.5 Ops/sec
classList	6269.0 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"); }