Run results for: getElementById vs querySelector vs getElementsByClassName vs getElementsByName

Run details:

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:87.0) Gecko/20100101 Firefox/87.0

Browser: Firefox 87

Operating system: Ubuntu

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