Run results for: shadow DOM vs light DOM

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36

Browser: Chrome 91

Operating system: Linux

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
light DOM	27138.8 Ops/sec
shadow DOM	29134.7 Ops/sec

HTML Preparation code:

<template id="tpl">
  <div>
	<h3>title example</h3>
    <p>example para with an <a href="#"><b>example link</b></a></p>
  </div>
</template>

<div id="container"></div>

Script Preparation code:

const tplNode = document.getElementById('tpl').content;
const container = document.getElementById('tpl');

class MyEl extends HTMLElement {
  connectedCallback() {
    this.appendChild(tplNode.cloneNode(true))
  }
}

customElements.define("my-el-lgt", MyEl);


class MyElWithShadowDOM extends HTMLElement {
  connectedCallback() {
    this.attachShadow({mode: 'open'});
    this.shadowRoot.appendChild(tplNode.cloneNode(true))
  }
}

customElements.define("my-el-shd", MyElWithShadowDOM);

Tests:

light DOM
container.innerHTML = ` <my-el-lgt></my-el-lgt> `
shadow DOM
container.innerHTML = ` <my-el-shd></my-el-shd> `