Run results for: document.getElementById, document.querySelector, element.querySelector

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:56.0) Gecko/20100101 Firefox/56.0

Browser: Firefox 56

Operating system: Mac OS X 10.11

Device Platform: Desktop

Date tested: 5 years ago

Test name	Executions per second
document.getElementById	5441639.0 Ops/sec
document.querySelector	1654648.0 Ops/sec
element.querySelector	5854899.0 Ops/sec

HTML Preparation code:

<header>Page header</header>
<nav>Navigation</nav>
<section id="content">
  <div id="nothing1"></div>
  <div id="nothing2"></div>
  <div id="nothing3"></div>
  <div id="container">
    <p><input id="testbutton" type="button" value="Test Button"></input></p>
  </div>
</section>
<footer>Page footer</footer>

Script Preparation code:

var container = document.getElementById("container");

Tests:

document.getElementById
document.getElementById("testbutton");
document.querySelector
document.querySelector("#testbutton");
element.querySelector
container.querySelector("#testbutton");