className VS classList Showdown

JavaScript performance comparison

Revision 5 of this test case created by Marcin

Info

How much faster is classList.add/remove than className regex manipulation?

Preparation code

<style type="text/css">
  .foo { color:#F00; height:100px; opacity:0.3; } .bar { color:#0F0; height:200px;
  opacity:0.5; } .baz { color:#00F; height:300px; opacity:0.7; }
</style>
<div id="base" class="foo bar">
  <div class="foo bar baz">
    test 1
  </div>
  <span class="foo bar">
    test 2
  </span>
  <span class="baz">
    test 3
  </span>
</div>
<script>
Benchmark.prototype.setup = function() {
    var node = document.getElementById('base'),
        className = 'baz';
   
    function addClass_className(el, className) {
      el.className += " " + className;
    }
   
   
    function removeClass_className(ele, cls) {
      var reg = new RegExp('(\\s|^)' + cls + '(\\s|$)');
      ele.className = ele.className.replace(reg, ' ').replace(/^\s\s*/, '').replace(/\s\s*$/, ''); //last 2 replaces do right trim (see http://blog.stevenlevithan.com/archives/faster-trim-javascript)
    }
};

Benchmark.prototype.teardown = function() {
    node.className = '';
};
</script>

Preparation code output

test 1
test 2 test 3

Test runner

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Testing in unknown unknown
Test Ops/sec
classList (add)
node.classList.add('foo');
node.classList.add('bar');
node.classList.add('baz');
pending…
className (add) walkontable 0.2.0
addClass_className(node, 'foo');
addClass_className(node, 'bar');
addClass_className(node, 'baz');
pending…
className raw
node.className = 'foo bar baz';
pending…

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Revisions

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