What is JavaScript?

JavaScript is the interpreted programming language that brings the web to life. Unlike HTML (structure) and CSS (design), JavaScript makes pages interactive and dynamic.

A bit of history

It was born in 1995, created by Brendan Eich in just 10 days. Even though it started as a “toy” for small tricks, today it is one of the most powerful and versatile languages in the world.

What does “client-side” mean?

When we say JS runs on the client, it means it executes directly in the browser of the person visiting the website. This allows it to:

• Modify the page in real time.
• Validate forms instantly.
• Create visual effects and animations.
• Communicate with servers without reloading the page.

And what about “server-side”?

Thanks to environments like Node.js, JavaScript can also be used to create the “brain” of applications that handles databases and files.

Entering or displaying data

There are several ways to interact with the user:

1. console.log(): Displays messages in the browser console (F12).
2. alert(): Shows a pop-up warning window.
3. prompt(): Opens a box for the user to enter text.
4. document.write(): Writes content directly into the HTML body (use with caution).

Example:

const name = prompt("What's your name?");
console.log("Hello, " + name);
alert("Welcome to Programierds");