Run results for: className vs. setAttribute vs. classList

Run details:

User agent: Mozilla/5.0 (Linux; Android 8.0.0; ASUS_Z017D Build/OPR1.170623.026) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.158 Mobile Safari/537.36

Browser: Opera.170623.026) applewebkit/537.36 (khtml, like gecko) chrome/66

Operating system: Android 8.0.0

Device Platform: Mobile

Date tested: 5 years ago

Test name	Executions per second
className	996.0 Ops/sec
setAttribute	828.2 Ops/sec
classList	660.7 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"); }