jQuery selector vs hasClass

JavaScript performance comparison

Test case created by Dan DeFelippi

Info

Test which is faster, a selector including the class compared to hasClass.

Preparation code

<script src="//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
<div class="foo"></div>
<script>
  var found = false;
  $("body").addClass("foobar");
</script>

Preparation code output

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Testing in unknown unknown
Test Ops/sec
selector
if ($("body.foobar").length) {
 found = true;
}
pending…
hasClass
if ($("body").hasClass("foobar")) {
 found = true;
}
pending…

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2 comments

Oskar commented :

Why does .hasClass() perform so much better?

Ignatius commented :

Because hasClass don't search the entire DOM, just the class atributte of the selected element.

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