getElementById vs. querySelector

JavaScript performance comparison

Revision 90 of this test case created

Info

Compare the speed of getElementById to querySelector

Preparation code

<p id="foo">Foo</p>
<p id="bar">Bar</p>
<p id="baz">Baz</p>
<p id1="foo">Foo</p>
<p id1="bar">Bar</p>
<p id1="baz">Baz</p>
<p id="foo">Foo</p>
<p id="bar">Bar</p>
<p id="baz">Baz</p>
<p id1="foo">Foo</p>
<p id1="bar">Bar</p>
<p id1="baz">Baz</p>
<p id="foo">Foo</p>
<p id="bar">Bar</p>
<p id="baz">Baz</p>
<p id1="foo">Foo</p>
<p id1="bar">Bar</p>
<p id1="baz">Baz</p>

Preparation code output

Foo

Bar

Baz

Foo

Bar

Baz

Foo

Bar

Baz

Foo

Bar

Baz

Foo

Bar

Baz

Foo

Bar

Baz

Test runner

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Testing in unknown unknown
Test Ops/sec
getElementById
var bar = document.getElementsByTagName("p");
if (!bar) {
  return;
}
var list = [];
for (var i = 0; i < bar.length; i++) {
  if (bar[i].getAttribute('id1')) {
    list.push(bar[i]);
  }
}
pending…
querySelector
var bar = document.querySelector("p[id1]");
pending…

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