getElementsByClassName[0] VS querySelector VS jQuery Selector

JavaScript performance comparison

Revision 189 of this test case created by

Preparation code

<script src="//code.jquery.com/jquery-2.2.1.min.js"></script>
<div>
  <ul>
    <li><a href="#" name="name" class="classname">item 1</a></li>
    <li><a href="#" name="name" class="classname">item 2</a></li>
    <li><a href="#" name="name" class="classname">item 3</a></li>
    <li><a href="#" name="name" class="classname">item 4</a></li>
    <li><a href="#" name="name" class="classname">item 5</a></li>
    <li><a href="#" name="name" class="classname">item 6</a></li>
    <li><a href="#" name="name" class="classname">item 7</a></li>
    <li><a href="#" name="name" class="classname">item 8</a></li>
    <li><a href="#" name="name" class="classname">item 9</a></li>
    <li><a href="#" name="name" class="classname">item 10</a></li>
  </ul>
</div>
<script>
  var node1, node2, node3, node4;
  function getFirstElementByClassName(classname) {
    var elems = document.getElementsByClassName(classname);
    return elems.length ? elems[0] : null;
  }
  function getFirstElementByJquery(selector) {
    var elems = $(selector);
    return elems.length ? elems[0] : null;
  }
</script>
    

Preparation code output

<div> <ul> <li><a href="#" name="name" class="classname">item 1</a></li> <li><a href="#" name="name" class="classname">item 2</a></li> <li><a href="#" name="name" class="classname">item 3</a></li> <li><a href="#" name="name" class="classname">item 4</a></li> <li><a href="#" name="name" class="classname">item 5</a></li> <li><a href="#" name="name" class="classname">item 6</a></li> <li><a href="#" name="name" class="classname">item 7</a></li> <li><a href="#" name="name" class="classname">item 8</a></li> <li><a href="#" name="name" class="classname">item 9</a></li> <li><a href="#" name="name" class="classname">item 10</a></li> </ul> </div>

Test runner

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
getElementsByClassName[0]
node1 = getFirstElementByClassName('classname');
pending…
querySelector
node2 = document.querySelector('.classname');
pending…
jQuery Selector
node3 = getFirstElementByJquery('.classname');
pending…
jQuery Attribute Selector
node4 = getFirstElementByJquery('[class="classname"]');
pending…

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Revisions

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