jQuery selector vs getElementsByTagName

JavaScript performance comparison

Revision 3 of this test case created by macem

Preparation code

<div class="pane">
<ul>
<li class="list"><a href="#">test</a></li>
<li class="list">test</li>
<li class="list">test</li>
<li class="list">test</li>
<li class="list">test</li>
<li class="list">test</li>
<li class="list">test</li>
<li class="list">test</li>
</ul>
</div>

<div class="pane">
<ul>
<li class="list"><a href="#">test</a></li>
<li class="list">test</li>
<li class="list">test</li>
<li class="list">test</li>
<li class="list">test</li>
<li class="list">test</li>
<li class="list">test</li>
<li class="list">test</li>
</ul>
</div><script src="//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>

<script>
  $.fn.tags = function (tagName) {
        var i=this.length,
            arr=[];
        for (i;i--;) {
                $.merge (arr, this[i].getElementsByTagName (tagName));
        }
        return $(arr);
  };
 
  var $links = $('.pane a'),
      $nodes;
</script>

Preparation code output

  • test
  • test
  • test
  • test
  • test
  • test
  • test
  • test
  • test
  • test
  • test
  • test
  • test
  • test
  • test
  • test

Test runner

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Testing in unknown unknown
Test Ops/sec
jQuery
$nodes = $('.pane li')[0];
pending…
jQuery method with getElementsByTagName
$nodes = $('.pane').tags('li')[0];
pending…

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Revisions

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