JavaScript Output

While you’re learning JavaScript, you need ways to see what your code is doing. JavaScript gives you four common ways to show output.

1. console.log() — For Developers

The most common way to see what your code is doing. It writes a message to the browser’s developer console (open it with F12 or Ctrl/Cmd + Shift + I).

console.log("Hello, console!");
console.log(2 + 2);
console.log({ name: "Ada", year: 1815 });

console.log() accepts anything — strings, numbers, objects, arrays. It’s the workhorse of JavaScript debugging.

2. innerHTML and textContent — Write to an Element

Most of the time, you actually want to display something on the page, not just in the console. Grab an element and set its content.

<p id="greeting"></p>
<script>
  document.getElementById("greeting").textContent = "Hello, page!";
</script>

• Use textContent when you want plain text.
• Use innerHTML when the value contains HTML (e.g. "<strong>bold</strong>").

3. alert() — Pop Up a Message

Shows a modal popup. Useful for quick experiments, almost never for production.

alert("Hello! I'm an alert.");

4. document.write() — For Quick Tests Only

Writes directly to the document.

<script>
  document.write("Hello from document.write!");
</script>

Which One Should You Use?

For the rest of this track, you’ll see console.log() in most examples and the DOM methods (textContent, innerHTML) when we’re working with a real page.

Up Next

Now that you can run code and see its output, let’s talk about how JavaScript code is structured.