Run results for: getElementById vs. querySelector

Run details:

User agent: Mozilla/5.0 (Linux; Android 9; Pixel 2 XL Build/PPR1.180610.009) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.91 Mobile Safari/537.36

Browser: Chrome Mobile 68

Operating system: Android

Device Platform: Mobile

Date tested: 6 years ago

Test name	Executions per second
getElementById	1450338.0 Ops/sec
querySelector	725456.7 Ops/sec
getElementById or querySelector	732287.2 Ops/sec

HTML Preparation code:

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

Tests:

getElementById
var bar = document.getElementById("bar");
querySelector
var bar = document.querySelector("#bar");
getElementById or querySelector
var selector = "#bar", func = selector.match('^#[A-z0-9-]*$') ? "getElementById" : "querySelector", bar = document[func]("bar");

Run results for: getElementById vs. querySelector

getElementById

querySelector

getElementById or querySelector