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

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:149.0) Gecko/20100101 Firefox/149.0

Browser: Firefox 149

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: 3 months ago

Test name	Executions per second
querySelectorAll + forEach	1614561.0 Ops/sec
getElementsByTagName + Array.from + forEach	1693292.6 Ops/sec
querySelectorAll + length + for	2469598.0 Ops/sec
getElementsByTagName + length + for	6509306.5 Ops/sec
querySelectorAll + dynamic length + for	1847030.4 Ops/sec
getElementsByTagName + dynamic length + for	3178803.5 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*/ }