Run results for: querySelectorAll vs getElementsByTagName + (fixed/dynamic) length + for

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:148.0) Gecko/20100101 Firefox/148.0

Browser: Firefox 148

Operating system: Windows

Device Platform: Desktop

Date tested: 3 months ago

Test name	Executions per second
querySelectorAll + forEach	1819649.4 Ops/sec
getElementsByTagName + Array.from + forEach	2461930.5 Ops/sec
querySelectorAll + length + for	2915295.0 Ops/sec
getElementsByTagName + length + for	9264009.0 Ops/sec
querySelectorAll + dynamic length + for	2333055.5 Ops/sec
getElementsByTagName + dynamic length + for	5100520.0 Ops/sec

HTML Preparation code:

<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>

Tests:

querySelectorAll + forEach
const allDivs = document.querySelectorAll('div'); allDivs.forEach(function (div) {});
getElementsByTagName + Array.from + forEach
const allDivs = document.getElementsByTagName('div'); const arrayAllDivs = Array.from(allDivs); arrayAllDivs.forEach(function (div) {});
querySelectorAll + length + for
const allDivs = document.querySelectorAll('div'); for (var i = 0, ilen = allDivs.length; i < ilen; i++) { /*NOOP*/ }
getElementsByTagName + length + for
const allDivs = document.getElementsByTagName('div'); for (var i = 0, ilen = allDivs.length; i < ilen; i++) { /*NOOP*/ }
querySelectorAll + dynamic length + for
const allDivs = document.querySelectorAll('div'); for (var i = 0; i < allDivs.length; i++) { /*NOOP*/ }
getElementsByTagName + dynamic length + for
const allDivs = document.getElementsByTagName('div'); for (var i = 0; i < allDivs.length; i++) { /*NOOP*/ }