Run results for: getElementsByClassName VS querySelectorAll (simple comparison)

Run details:

User agent: Mozilla/5.0 (Linux; Android 12; SM-S908E Build/SP1A.210812.016; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/101.0.4951.61 Mobile Safari/537.36

Browser: Chrome Mobile 101

Operating system: Android

Device Platform: Mobile

Date tested: 2 years ago

Test name	Executions per second
The method getElementsByClassName()	4499541.0 Ops/sec
The method querySelectorAll()	828992.1 Ops/sec

HTML Preparation code:

<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>

Tests:

The method getElementsByClassName()
document.getElementById("example container");
The method querySelectorAll()
document.querySelectorAll(".example.container");

Run results for: getElementsByClassName VS querySelectorAll (simple comparison)

A simple comparison of performance between these two methods. (Medium, @benlmsc)

The method getElementsByClassName()

The method querySelectorAll()