Run results for: Query Selector v Sizzle

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36 OPR/68.0.3618.206

Browser: Opera 68

Operating system: Windows

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
qs ID	888923.6 Ops/sec
qs Class	414204.9 Ops/sec
sizzle ID	383116.2 Ops/sec
sizzle Class	301945.6 Ops/sec

HTML Preparation code:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.4/jquery.min.js"></script>

<div id="test" class="m">a</div>
<div class="m">b</div>

Script Preparation code:

var select = function(selector) {
	if (!selector) return null
	
	if (selector.charAt(0) == '#') {
		return document.querySelector(selector)
	} else {
		var result = document.querySelectorAll(selector)
		switch (result.length) {
			case 0:
				return null
			case 1:
				return result[0]
			default:
				return result
		}
	}
}

Tests:

qs ID
select('#test')
qs Class
select('.m')
sizzle ID
$('#test')
sizzle Class
$('.m')

Run results for: Query Selector v Sizzle

qs ID

qs Class

sizzle ID

sizzle Class