Benchmark: getElementById and getElementsByClassName [0] vs querySelector

HTML Preparation code:

<div id="testdiv">
  <div id="unique1" class="unique" name="unique" data-unique="1">test1</div>
  <div id="unique2" class="unique" name="unique" data-unique="2">test2</div>
  <div id="unique3" class="unique" name="unique" data-unique="3">test3</div>
  <div id="unique4" class="unique" name="unique" data-unique="4">test4</div>
  <div id="unique5" class="unique" name="unique" data-unique="5">test5</div>
</div>

Script Preparation code:

var i, imax;
var doc = document;

Tests:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
getElementById
querySelector
getElementById and getElementsByClassName

Fastest: N/A

Slowest: N/A

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Latest run results:

Run details: (Test run date: 2 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser/OS: Chrome 120 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
getElementById	13874970.0 Ops/sec
querySelector	7117081.0 Ops/sec
getElementById and getElementsByClassName	7057708.0 Ops/sec

getElementById and getElementsByClassName [0] vs querySelector (version: 0)

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

Comparing performance of: getElementById vs querySelector vs getElementById and getElementsByClassName

Created: 4 years ago by: Guest

Jump to the latest result

getElementById

querySelector

getElementById and getElementsByClassName

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A