Run results for: DOM get attributes of children vs JS Array READ performance

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.54 Safari/537.36

Browser: Chrome 95

Operating system: Linux

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
fastest iter childelements	1264905.4 Ops/sec
tag name	827169.4 Ops/sec
class name	810626.9 Ops/sec
id	608968.5 Ops/sec
array of node	792838.8 Ops/sec
array item	2102137.2 Ops/sec
fastest iter childelements + getAttribute	2078095.9 Ops/sec

HTML Preparation code:

<html>

<body>
    <div id='test'>
        <div class='item' id='a' name='a'></div>
        <div class='item' id='b' name='b'></div>
        <div class='item' id='c' name='c'></div>
    </div>
</body>

</html>

Script Preparation code:

var parent = document.getElementById('test');

var store1 = [];
var store2 = [];
parent.childNodes.forEach(function (node) {
  if ( node.nodeName !== '#text') {
  store1.push( node );
  store2.push( { name: node.attributes.name.value } );
  }
});

Tests:

fastest iter childelements
let elem = parent.firstElementChild; do { let n = elem.attributes.name.value; } while (elem = elem.nextElementSibling)
tag name
let children = parent.getElementsByTagName('div'); for (let i = 0; i < children.length; i++) { let n = children[i].attributes.name.value; }
class name
let children = parent.getElementsByClassName('item') for (let i = 0; i < children.length; i++) { let n = children[i].attributes.name.value; }
id
let n1 = document.getElementById('a').attributes.name.value; let n2 = document.getElementById('b').attributes.name.value; let n3 = document.getElementById('c').attributes.name.value;
array of node
for (let i = 0; i < store1.length; i++) { let n = store1[i].attributes.name.value; }
array item
for (let i = 0; i < store2.length; i++) { let n = store2[i].name; }
fastest iter childelements + getAttribute
let elem = parent.firstElementChild; do { let n = elem.getAttribute('name'); } while (elem = elem.nextElementSibling)

Run results for: DOM get attributes of children vs JS Array READ performance

Results: Reading the DOM with nextElementSibling + getAttribute is less than 5% slower than an JS array list

fastest iter childelements

tag name

class name

id

array of node

array item

fastest iter childelements + getAttribute