Run results for: querySelector vs getElementsByTagName simple select

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/148.0.0.0 Safari/537.36 Edg/148.0.0.0

Browser: Chrome 148

Operating system: Windows

Device Platform: Desktop

Date tested: 2 months ago

getElementsByTagName for none existing element

33.6M/s

getElementsByTagName for existing element

31.1M/s

querySelector for none existing element

19.4M/s

querySelector for existing element

18.8M/s

View exact numbers

Test name	Executions per second
✓ getElementsByTagName for none existing element	33,616,616 Ops/sec
getElementsByTagName for existing element	31,130,122 Ops/sec
querySelector for none existing element	19,398,800 Ops/sec
querySelector for existing element	18,810,404 Ops/sec

HTML Preparation code:

<div>
  <test><test2></test2></test>
  <test><test2><test3></test3></test2></test>
  <test></test>
</div>

Tests:

querySelector for existing element
const found = document.querySelector('div');
getElementsByTagName for existing element
const found = document.getElementsByTagName('div');
querySelector for none existing element
const found = document.querySelector('span');
getElementsByTagName for none existing element
const found = document.getElementsByTagName('span');