Run results for: className vs. setAttribute vs. classList

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.103 Safari/537.36

Browser: Chrome 73

Operating system: Windows

Device Platform: Desktop

Date tested: 5 years ago

Test name	Executions per second
className	1.3 Ops/sec
classList	2.8 Ops/sec

HTML Preparation code:

<div id="foo" class="lorem"></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; while (i--) { element.classList.add("bar"); }