html Archives | JS FAQ - JavaScript Guides Online

How to create a new HTML element in JavaScript

Efficient DOM manipulation involves creating fully configured elements before insertion to minimize reflows. Use DocumentFragment for batch appends, manipulate styles via the style property, manage classes with classList API, clone nodes with cloneNode(true), and prefer direct property assignments for faster attribute setting.

Web Components

How to define a custom HTML tag in JavaScript

Web Componentscustom tag, html, js components, web components

Custom elements lifecycle callbacks are essential for managing state in web components. Key methods include connectedCallback for DOM insertion, disconnectedCallback for cleanup, and attributeChangedCallback for dynamic attributes. These callbacks enhance interactivity and efficiency, ensuring components respond effectively to their environment.

JS Basics

How to include JavaScript in an HTML file

JS Basicsembed, html, js basics, script tag

Add JavaScript to HTML with inline or external script tags. To prevent render-blocking and improve page load speed, place scripts before the closing body tag. For optimal performance, use the defer attribute for ordered execution or async for independent third-party scripts in the head.