Run results for: className vs classList

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0

Browser: Firefox 115

Operating system: Linux

Device Platform: Desktop

Date tested: 2 years ago

classList

2K/s

className

2/s

View exact numbers

Test name	Executions per second
✓ classList	1,771 Ops/sec
className	2 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"); }