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/68.0.3440.75 Safari/537.36 OPR/55.0.2994.29 (Edition beta)

Browser: Opera 55

Operating system: Windows

Device Platform: Desktop

Date tested: 5 years ago

Test name	Executions per second
className	496.0 Ops/sec
setAttribute	434.0 Ops/sec
classList	1022.7 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"); }