Run results for: querySelector(class) vs classList.contains

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36

Browser: Chrome 123

Operating system: Windows

Device Platform: Desktop

Date tested: 8 months ago

Test name	Executions per second
querySelector	1568046.0 Ops/sec
classList.contains	4936618.0 Ops/sec
querySelector after more HTML elements	875125.3 Ops/sec
classList.contains after more HTML elements	4812829.5 Ops/sec

HTML Preparation code:

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<div class='a c'>howAboutMoreElements</div>

Script Preparation code:

function querySelectorWrapper(className) {
    return !document.querySelector('.' + className);
}

function classListContainsWrapper(element, className) {
    return element.classList.contains(className);
}
var elementRefB = document.querySelector('.b');
var elementRefC = document.querySelector('.c');

Tests:

querySelector
querySelectorWrapper('b');
classList.contains
classListContainsWrapper(elementRefB, 'b');
querySelector after more HTML elements
querySelectorWrapper('c');
classList.contains after more HTML elements
classListContainsWrapper(elementRefC, 'c');

Run results for: querySelector(class) vs classList.contains

HTML DOM querySelector, vs looking into classList of element which already have

querySelector

classList.contains

querySelector after more HTML elements

classList.contains after more HTML elements