Run results for: getElementById vs querySelector(css) vs getElementsByClassName vs getElementsByName

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.72 Safari/537.36

Browser: Chrome 90

Operating system: Windows

Device Platform: Desktop

Date tested: 3 years ago

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.querySelector('#testdiv .unique').innerHTML;
getElementsByClassName
var test = doc.getElementById('testdiv').getElementsByClassName('unique')[0].innerHTML;
getElementById unique
var formelem = doc.getElementById('unique').innerHTML;
querySelector (unique id)
var formelem = doc.querySelector('#unique').innerHTML;