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: 6 months ago

Benchmark engine: Benchmark.js

Test name	Executions per second
✓ getElementsByTagName + length + for	6,509,306 Ops/sec
getElementsByTagName + dynamic length + for	3,178,804 Ops/sec
querySelectorAll + length + for	2,469,598 Ops/sec
querySelectorAll + dynamic length + for	1,847,030 Ops/sec
getElementsByTagName + Array.from + forEach	1,693,293 Ops/sec
querySelectorAll + forEach	1,614,561 Ops/sec

Test name

Executions per second

✓ getElementsByTagName + length + for

6,509,306 Ops/sec

getElementsByTagName + dynamic length + for

3,178,804 Ops/sec

querySelectorAll + length + for

2,469,598 Ops/sec

querySelectorAll + dynamic length + for

1,847,030 Ops/sec

getElementsByTagName + Array.from + forEach

1,693,293 Ops/sec

querySelectorAll + forEach

1,614,561 Ops/sec

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*/ }