Caching jQuery Objects

JavaScript performance comparison

Revision 25 of this test case created by Shawn Terry

Info

This test compares the performance impact of three different jQuery scenarios:

1) Multiple selectors, multiple statements 2) Cached selector, multiple statements 3) Cached selector, chained statements

The goal is to identify the best way to handle jQuery selectors for optimum performance.

Preparation code

<script src="//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>

<!--Sample DOM-->
<header>
<h1>Sample DOM</h1>
</header>
<nav>
<ul>
<li>Item 1</li>
<li>Item 2</li>
<li>Item 3</li>
</ul>
</nav>
<div id="main">
  <div id="content">
  <div id="myDiv" class="myClass">
  <p>Sample content of non-consequence</p>
  </div>
  </div>
</div>
<footer>
<a href="#">Terms</a>
</footer>

Preparation code output

Sample DOM

Sample content of non-consequence

Test runner

Warning! For accurate results, please disable Firebug before running the tests. (Why?)

Java applet disabled.

Testing in unknown unknown
Test Ops/sec
No Caching
$("#myDiv").css({'color':'red','opacity':'1','display':'block'});
$("#myDiv").attr('data-testcase','No caching');
$("#myDiv").removeClass('doesNotExist').addClass('doesNotExist');
pending…
Object Caching
var jqoMyDiv = $("#myDiv");
jqoMyDiv.css({'color':'red','opacity':'1','display':'block'});
jqoMyDiv.attr('data-testcase','Use caching');
jqoMyDiv.removeClass('doesNotExist').addClass('doesNotExist');
pending…
Object Caching + Chaining
var jqoMyDiv = $("#myDiv");
jqoMyDiv.css({'color':'red','opacity':'1','display':'block'}).attr('data-testcase','Use caching and chaining').removeClass('doesNotExist').addClass('doesNotExist');
pending…

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