Say Hello to the Browser

Welcome to the JavaScript course! In this lesson, you’ll write your very first lines of code—and get the browser to respond. Instant feedback, no setup, just results.

Goal

You’ll aim to:

• Write your first JavaScript commands.

• Display messages using console.log() and alert().

• See instant output in the browser.

Talk to the browser

JavaScript is how we make the web do things. And it starts with just talking—like this:

Printing a message to the console

That line tells the browser: “Say this in the console.”

Notice how we've wrapped the text in double quotation marks. These quotation marks tell JavaScript that "Hello World" is a string—a sequence of characters meant to be read as text. The console.log() function then logs exactly what’s inside the quotation marks to the console.

Try a pop-up alert

Want your message to pop up right on the screen, like those little messages you sometimes see when visiting websites? Let's try that now!

Showing a pop-up alert

For this, we use alert() instead:

This is hard to miss—it grabs attention, just like those alerts or confirmation boxes you’ve probably seen on websites. It's a simple way to show important info while you're learning JavaScript.

Try it yourself

Change the message to anything you want:

or

Explanation

• console.log()= Send a message to the browser console.

• alert() = Show a pop-up message to the user.

• Strings must go inside quotes: "like this" or 'like this'.

• Every line ends with a semicolon ; (optional but recommended).

Let’s practice

Now, let’s lock in what you’ve just learned with a quick quiz in the next lesson to help you reinforce your understanding before we move on.