Run results for: test children matches vs classList vs querySelectorAll vs getElementsByClassName v.2

Run details:

User agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:109.0) Gecko/20100101 Firefox/115.0

Browser: Firefox 115

Operating system: Windows 8.1

Device Platform: Desktop

Date tested: one year ago

getElementsByClassName

1039.2M/s

querySelectorAll

30K/s

className (for)

6K/s

classList (for)

6K/s

className (filter)

6K/s

classList (filter)

6K/s

matches (for)

5K/s

matches (filter)

5K/s

View exact numbers

Test name	Executions per second
✓ getElementsByClassName	1,039,225,408 Ops/sec
querySelectorAll	30,390 Ops/sec
className (for)	6,018 Ops/sec
classList (for)	5,834 Ops/sec
className (filter)	5,750 Ops/sec
classList (filter)	5,623 Ops/sec
matches (for)	5,061 Ops/sec
matches (filter)	4,716 Ops/sec

HTML Preparation code:

<div id="test"></div>

Script Preparation code:

const count = 1000;
const holder = document.getElementById('test');

for (let i = 0; i < count; i++) {
   let elem = document.createElement('div');
   elem.classList.add(0|Math.random()*2 ? 'foo' : 'bar');
   holder.appendChild(elem);
}

Tests:

matches (filter)
const result = Array.from(holder.children).filter((node) => node.matches('.foo'));
matches (for)
const result = []; for (const child of holder.children) { if (child.matches('.foo')) result.push(child); }
classList (filter)
const result = Array.from(holder.children).filter((node) => node.classList.contains('foo'));
classList (for)
const result = []; for (const child of holder.children) { if (child.classList.contains('foo')) result.push(child); }
className (filter)
const result = Array.from(holder.children).filter((node) => node.className.includes('foo'));
className (for)
const result = []; for (const child of holder.children) { if (child.className.includes('foo')) result.push(child); }
querySelectorAll
const result = holder.querySelectorAll(':scope > .foo');
getElementsByClassName
const result = holder.getElementsByClassName('foo');