Run results for: querySelectorAll vs getElementsByTagName 24

Run details:

User agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.113 Safari/537.36

Browser: Chrome 81

Operating system: Windows 7

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
querySelectorAll	147958.0 Ops/sec
getElementsByTagName	87958.6 Ops/sec
getElementsByTagName ArrayFrom	87384.4 Ops/sec
getElementsByTagName ForLoop	135925.4 Ops/sec
getElementsByTagName ArrayFilterForEach	95395.5 Ops/sec
getElementsByTagName ArrayFilterMap	93459.4 Ops/sec

HTML Preparation code:

<div>
<img />
<img />
<img />
<img loading /> 
<img loading /> 
<img loading = "lazy" />
</div>
<div>
<img />
<img />
<img />
<img loading /> 
<img loading /> 
<img loading = "lazy" />
</div>

Tests:

querySelectorAll
document.querySelectorAll('img[loading]').forEach(i => { i.setAttribute('loading', 'eager'); });
getElementsByTagName
[...document.getElementsByTagName('img')].forEach(i => { if (typeof i.loading !== "undefined") i.setAttribute('loading', 'eager'); });
getElementsByTagName ArrayFrom
Array.from(document.getElementsByTagName('img')).forEach(i => { if (typeof i.loading !== "undefined") i.setAttribute('loading', 'eager'); });
getElementsByTagName ForLoop
const imgs = document.getElementsByTagName('img'); for (let i = 0; i < imgs.length; i++) { if (typeof imgs[i].loading !== "undefined") imgs[i].setAttribute('loading', 'eager'); }
getElementsByTagName ArrayFilterForEach
[].filter.call(document.getElementsByTagName('img'), i => i.hasAttribute('loading')).forEach(i => i.setAttribute('loading', 'eager'));
getElementsByTagName ArrayFilterMap
[].filter.call(document.getElementsByTagName('img'), i => i.hasAttribute('loading')).map(i => i.setAttribute('loading', 'eager'));

Run results for: querySelectorAll vs getElementsByTagName 24

querySelectorAll

getElementsByTagName

getElementsByTagName ArrayFrom

getElementsByTagName ForLoop

getElementsByTagName ArrayFilterForEach

getElementsByTagName ArrayFilterMap