Vanilla JS Theme Toggle - JavaScript Typing CST Test
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Vanilla JS Theme Toggle — JavaScript Code
Toggles between light and dark themes using class manipulation.
document.addEventListener('DOMContentLoaded', () => {
const toggleBtn = document.getElementById('toggleTheme');
const appEl = document.getElementById('app');
let isDark = false;
toggleBtn.addEventListener('click', () => {
isDark = !isDark;
appEl.className = isDark ? 'dark-theme' : 'light-theme';
toggleBtn.textContent = `Switch to ${isDark ? 'Light' : 'Dark'} Theme`;
});
});JavaScript Language Guide
JavaScript is a high-level, interpreted programming language primarily used to create dynamic and interactive content on web pages. It enables client-side scripting, DOM manipulation, and integration with HTML and CSS.
Primary Use Cases
- ▸Adding interactivity to web pages
- ▸Manipulating the DOM and HTML elements dynamically
- ▸Form validation and user input handling
- ▸Creating web applications and single-page applications (SPA)
- ▸Server-side development with Node.js
Notable Features
- ▸Event handling and listeners
- ▸Asynchronous programming with Promises and async/await
- ▸Prototype-based object-oriented programming
- ▸Dynamic typing and flexible syntax
- ▸Extensive ecosystem of libraries and frameworks (React, Angular, Vue)
Origin & Creator
Created by Brendan Eich in 1995 at Netscape Communications.
Industrial Note
JavaScript is specialized for web interactivity, dynamic content updates, and client-side logic, but it is also widely used for server-side applications via Node.js.