Run results for: tagName vs instanceof

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36

Browser: Chrome 124

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

localName

4.7M/s

nodeName

4.7M/s

tagName

4.7M/s

__proto__

4.3M/s

instanceof

3.9M/s

View exact numbers

Test name	Executions per second
✓ localName	4,745,300 Ops/sec
nodeName	4,693,380 Ops/sec
tagName	4,686,348 Ops/sec
__proto__	4,275,218 Ops/sec
instanceof	3,917,832 Ops/sec

Script Preparation code:

var xs = [];
var n = 0;

for (let i = 0; i < 1000; ++i) {
  xs[i] = (Math.random() > .5) ? document.createElement(`div`) : document.createElement(`span`);
};

Tests:

instanceof
n += ((xs[(Math.random() * 1000)|0]) instanceof HTMLDivElement)|0;
tagName
n += (xs[(Math.random() * 1000)|0].tagName === `DIV`)|0;
nodeName
n += (xs[(Math.random() * 1000)|0].nodeName === `DIV`)|0;
localName
n += (xs[(Math.random() * 1000)|0].localName === `div`)|0;
__proto__
n += ((xs[(Math.random() * 1000)|0]).__proto__ === HTMLDivElement.prototype)|0;