Run results for: tagName vs instanceof

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36 Edg/129.0.0.0

Browser: Chrome 129

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

localName

1.4M/s

tagName

1.3M/s

nodeName

1.3M/s

__proto__

1.2M/s

instanceof

1.2M/s

View exact numbers

Test name	Executions per second
✓ localName	1,408,576 Ops/sec
tagName	1,337,736 Ops/sec
nodeName	1,330,555 Ops/sec
__proto__	1,249,926 Ops/sec
instanceof	1,183,409 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;