Run results for: className.indexOf vs. classList.contains

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.54 Safari/537.36

Browser: Chrome 101

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
className	13348.6 Ops/sec
classList	5667.2 Ops/sec

HTML Preparation code:

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

Tests:

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