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 10.14; rv:77.0) Gecko/20100101 Firefox/77.0

Browser: Firefox 77

Operating system: Mac OS X 10.14

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
querySelector	3110090.0 Ops/sec
querySelectorAll	1373928.0 Ops/sec
getElementsByClassName	5131337.0 Ops/sec
querySelector (ID)	2966609.0 Ops/sec
getElementsByID	5345908.0 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")