Run results for: form.elements vs getElementsByTagName vs querySelectorAll

Run details:

User agent: Mozilla/5.0 (Windows NT 5.1; rv:52.0) Gecko/20100101 Firefox/52.0

Browser: Firefox 52

Operating system: Windows XP

Device Platform: Desktop

Date tested: 2 years ago

getElementsByName

252K/s

getElementsByTagName

224K/s

getElementsByClassName

216K/s

form.elements

214K/s

querySelectorAll

123K/s

View exact numbers

Test name	Executions per second
✓ getElementsByName	252,362 Ops/sec
getElementsByTagName	223,853 Ops/sec
getElementsByClassName	215,929 Ops/sec
form.elements	214,463 Ops/sec
querySelectorAll	122,608 Ops/sec

HTML Preparation code:

<form id="testform">
  <input value="test" />
  <input value="testing" />
</form>
<div id="testdiv">
  <input class="unique" name="unique" data-unique="1" value="test" />
  <input class="unique" name="unique" data-unique="1" value="testing" />
  <!-- added following divs to try and knock getElementsByClassName and getElementsByName out of the running-->
  <div class="test1" name="test1">
    <div class="test6" name="test6">&nbsp;</div>
  </div>
  <div class="test2" name="test2">
    <div class="test7" name="test7">&nbsp;</div>
  </div>
  <div class="test3" name="test3">
    <div class="test8" name="test8">&nbsp;</div>
  </div>
  <div class="test4" name="test4">
    <div class="test9" name="test9">&nbsp;</div>
  </div>
  <div class="test5" name="test5">
    <div class="test1" name="test1">&nbsp;</div>
  </div>
</div>

Script Preparation code:

var i, imax;
var doc = document;

Tests: