Run results for: CssText vs Styling vs classList add

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.3 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 18

Operating system: iOS 18.3

Device Platform: Mobile

Date tested: one year ago

classList add

11.2M/s

styling

4.2M/s

csstext

688K/s

View exact numbers

Test name	Executions per second
✓ classList add	11,162,162 Ops/sec
styling	4,187,561 Ops/sec
csstext	688,349 Ops/sec

HTML Preparation code:

<div id="myid">hi</div>
<style>
    .wide {
      width: 100px;
    }
    .long {
      left: 100px;
      height: 100px;
    }
    .blue {
      top: 100px;
    }
</style>

Script Preparation code:

var a = document.getElementById("myid");
a.style.position = "absolute";

Tests:

csstext
a.style.cssText += "left: 100px ;top: 100px; width: 100px; height: 100px";
styling
a.style.left = "100px" a.style.top = "100px" a.style.width = "100px" a.style.height = "100px"
classList add
a.classList.add('wide','long','blue')