Run results for: classList.contains VS dataset

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_3_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) FxiOS/135 Mobile/15E148 Version/15.0

Browser: Mobile Safari 15

Operating system: iOS 18.3.1

Device Platform: Mobile

Date tested: one year ago

classList

67K/s

className

12K/s

View exact numbers

Test name	Executions per second
✓ classList	66,531 Ops/sec
className	12,038 Ops/sec

HTML Preparation code:

<div id="foo" class="test" data-class-test="1" ></div>

Tests:

className
var element = document.getElementById("foo"); var i = 1000; while (i--) { if (element.dataset.classTest == 1) {} }
classList
var element = document.getElementById("foo"); var i = 1000; while (i--) { element.classList.contains("test"); }