Run results for: querySelector vs querySelectorAll vs getElementsByClassName vs querySelector (ID) vs getElementsByID - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:94.0) Gecko/20100101 Firefox/94.0

Browser: Firefox 94

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
querySelector	3685438.0 Ops/sec
querySelectorAll	1426923.0 Ops/sec
getElementsByClassName	6204392.0 Ops/sec
querySelector (ID)	3692655.0 Ops/sec
getElementsByID	6745492.0 Ops/sec

Website performance monitoring

HTML Preparation code:

<div class="test" id="test"></div>

Tests:

querySelector
document.querySelector(".test")
querySelectorAll
document.querySelectorAll(".test")
getElementsByClassName
document.getElementsByClassName(".test")
querySelector (ID)
document.querySelector("#test")
getElementsByID
document.getElementById("test")