Run results for: className vs. setAttribute vs. classList

Run details:

User agent: Mozilla/5.0 (Linux; Android 9; ONEPLUS A6003 Build/PKQ1.180716.001) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.90 Mobile Safari/537.36 OPR/52.2.2517.139816

Browser: Opera Mobile 52

Operating system: Android

Device Platform: Mobile

Date tested: 4 years ago

Test name	Executions per second
className	2274.4 Ops/sec
setAttribute	1312.1 Ops/sec
classList	1298.2 Ops/sec

HTML Preparation code:

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

Tests:

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