Run results for: className vs. setAttribute vs. classList

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.121 Safari/537.36 OPR/71.0.3770.198

Browser: Opera 71

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
className	281.6 Ops/sec
setAttribute	226.1 Ops/sec
classList	160.1 Ops/sec

HTML Preparation code:

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

Tests:

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