Run results for: className vs. classList (comparing and adding)1

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.139 Safari/537.36

Browser: Chrome 66

Operating system: Windows

Device Platform: Desktop

Date tested: 6 years ago

Test name	Executions per second
className	3171.4 Ops/sec
classList	2421.3 Ops/sec

HTML Preparation code:

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

Tests:

className
var element = document.getElementById("foo"); var i = 1000; while (i--) { if(element.className.indexOf("test") > -1) { element.className = "bar"; }else { element.className = "test"; } }
classList
var element = document.getElementById("foo"); var i = 1000; while (i--) { if(element.classList.contains("test")) { element.classList.add("bar"); } else { element.classList.add("test"); } }