getElementsByTagname("a")[0] vs. querySelector("a")

JavaScript performance comparison

Revision 7 of this test case created by Jorge Chamorro

Preparation code

<ul>
  <li><a href="#">Item</a></li>
  <li><a href="#">Item</a></li>
  <li><a href="#">Item</a></li>
  <li><a href="#">Item</a></li>
  <li><a href="#">Item</a></li>
</ul>
    

Preparation code output

<ul> <li><a href="#">Item</a></li> <li><a href="#">Item</a></li> <li><a href="#">Item</a></li> <li><a href="#">Item</a></li> <li><a href="#">Item</a></li> </ul>

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
Using getElementsByTagName()
var list = document.getElementsByTagName("a");
var i = list.length;
var results = [];

while (i--) {
 results.push(list[i]);
}
pending…
Using querySelectorAll()
var list = document.querySelectorAll("a");
var i = list.length;
var results = [];

while (i--) {
 results.push(list[i]);
}
pending…

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Revisions

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