Run results for: className vs. setAttribute vs. classList vs. dataset v2

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 26_2_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/144.0.7559.95 Mobile/15E148 Safari/604.1

Browser: Chrome Mobile iOS 144

Operating system: iOS 26.2.0

Device Platform: Mobile

Date tested: 7 months ago

Benchmark engine: Benchmark.js

className

53K/s

setAttribute

24K/s

classList

23K/s

dataset

11K/s

View exact numbers

Test name	Executions per second
✓ className	52,910 Ops/sec
setAttribute	24,367 Ops/sec
classList	22,696 Ops/sec
dataset	10,756 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"); }
dataset
var element = document.getElementsByTagName("div")[0]; var i = 1000; while (i--) { element.dataset.foo = 'bar'; }