JavaScript works by running inside the browser. When a user opens a webpage, the browser first loads the HTML to create the structure, then applies CSS for design, and finally runs JavaScript to add interaction.
This happens very quickly, which makes websites feel fast and responsive. JavaScript allows pages to change content, respond to clicks, validate forms, and communicate with users without reloading the page.
Understanding how JavaScript works helps developers write better code and fix errors more easily.
How JavaScript Works Step by Step
1. User opens a webpage
2. Browser reads the HTML file
3. CSS styles are applied
4. JavaScript code is executed
5. The webpage becomes interactive
This is why JavaScript is often called the brain of a website.
This code prints a message in the browser console. Developers use the console to test code, check values, and find errors while building applications.
In this example, JavaScript listens for a user action. When the button is clicked, the function runs and shows a message.
This proves that JavaScript can respond to user behavior and make webpages interactive instead of static.
This example shows how JavaScript handles data and displays information dynamically. In real applications, similar logic is used in dashboards, counters, notifications, and tracking systems.
Knowing how JavaScript works is a basic but very important skill for frontend developers and is often tested in interviews.