Access to nodes via querySelectorAll vs getElementsByTagName (v7)

Revision 7 of this benchmark created on

Description

we discovered that calling getelementsbytagname('DIV') is a way faster than queryselectorall('DIV') http://www.nczonline.net/blog/2010/09/28/why-is-getelementsbytagname-faster-that-queryselectorall

the reason being that the former returns an HTMLCollection (live list) and the later a NodeList (static list). To go further we will see if accessing properties of a static list compensates the time to create it

Preparation HTML

<div>
  <ul>
    <li><a href="#">item 1</a></li>
    <li><a href="#">item 2</a></li>
    <li><a href="#">item 3</a></li>
    <li><a href="#">item 4</a></li>
    <li><a href="#">item 5</a></li>
    <li><a href="#">item 6</a></li>
    <li><a href="#">item 7</a></li>
    <li><a href="#">item 8</a></li>
    <li><a href="#">item 9</a></li>
    <li><a href="#">item 10</a></li>
    <li><a href="#">item 11</a></li>
    <li><a href="#">item 12</a></li>
    <li><a href="#">item 13</a></li>
    <li><a href="#">item 14</a></li>
    <li><a href="#">item 15</a></li>
    <li><a href="#">item 16</a></li>
    <li><a href="#">item 17</a></li>
  </ul>
</div>

Test runner

Ready to run.

Testing in
TestOps/sec
querySelectorAll
var href;
for (var i of document.querySelectorAll('a')) {
 href = i.href;
 i.href = 'another url';
}
ready
getElementsByTagName
var nodes = document.getElementsByTagName('a');
for (var i = 0, iLength = nodes.length; i < iLength; i++) {
 href = nodes[i].href;
 nodes[i].href = 'another url';
}
ready

Revisions

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