Run results for: getElementById vs querySelector vs getElementsByClassName vs getElementsByName

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.60 YaBrowser/20.12.0.963 Yowser/2.5 Safari/537.36

Browser: Yandex Browser 20

Operating system: Windows

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
getElementById	3873856.0 Ops/sec
getElementsByTagName	1587089.9 Ops/sec
querySelector	2420801.8 Ops/sec
getElementsByClassName	2134912.2 Ops/sec
getElementsByName	2404472.2 Ops/sec

HTML Preparation code:

<div id="testdiv">
  <div id="unique" class="unique" name="unique" data-unique="1">test</div>
</div>

Script Preparation code:

var i, imax;
var doc = document;

Tests:

getElementById
var test = doc.getElementById('testdiv').childNodes[0].innerHTML;
getElementsByTagName
var formelem = doc.getElementById('testdiv').getElementsByTagName('div')[0].innerHTML;
querySelector
var test = doc.getElementById('testdiv').querySelector('.unique').innerHTML;
getElementsByClassName
var test = doc.getElementById('testdiv').getElementsByClassName('unique')[0].innerHTML;
getElementsByName
var test = doc.getElementsByName('unique')[0].innerHTML;

Run results for: getElementById vs querySelector vs getElementsByClassName vs getElementsByName

Test performance of different ways of get just one particular DOM element

getElementById

getElementsByTagName

querySelector

getElementsByClassName

getElementsByName