Run results for: className vs classList

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:150.0) Gecko/20100101 Firefox/150.0

Browser: Firefox 150

Operating system: Windows

Device Platform: Desktop

Date tested: 23 hours ago

Test name	Executions per second
className	2.8 Ops/sec
classList	5519.1 Ops/sec

HTML Preparation code:

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

Tests:

className
var element = document.getElementById("foo"); var i = 1000; while (i--) { element.className += "bar "; }
classList
var element = document.getElementById("foo"); var i = 1000; var cl = element.classList; while (i--) { cl.add("bar"); }