Loading indicators

Part of the JavaScript in Action section of Coddy's HTML journey — lesson 10 of 27.

Loading indicators are small visual elements (like spinners or animations) that let users know something is happening in the background (when submitting a form or loading data). They improve user experience by showing feedback instead of leaving the user guessing.

First, add this HTML to your page:

<button id="loadBtn">Load Data</button>
<div id="loading-spinner" class="spinner-hidden">
  <div class="spinner"></div>
</div>

Then, add CSS to style the element so it looks like a wheel, and use keyframes to keep spinning it endlessly. We also use a .hidden class to keep the spinner invisible when needed.

.spinner {
  width: 40px;
  height: 40px;
  border: 4px solid #f3f3f3;
  border-top: 4px solid #3498db;
  border-radius: 50%;
  animation: spin 1s linear infinite;
}
.hidden {
  display: none;
}
@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

Now, add JavaScript to show/hide the spinner:

const loadBtn = document.getElementById("loadBtn");
const spinner = document.getElementById("spinner");

loadBtn.addEventListener("click", function () {
  // Show spinner
  spinner.classList.remove("hidden");

  // After 3 seconds, hide spinner and show alert
  setTimeout(function () {
    spinner.classList.add("hidden");
    alert("Data loaded successfully!");
  }, 3000);
});

When the button is clicked, we show the spinner, wait 3 seconds, then hide it and display an alert.

Challenge

Easy

Your task:

Inside the button's click event listener, add code to show the spinner by removing the "hidden" class. Place this code before the setTimeout function.

Try it yourself

<!DOCTYPE html>
<html>
<head>
  <title>Loading Spinner Example</title>
  <link rel="stylesheet" href="style.css">
</head>
<body>
  <div class="container">
    <h1>Welcome to My Page</h1>
    <p>Click the button below to simulate loading data.</p>
    <button id="loadBtn">Load Data</button>
    <div id="spinner" class="spinner hidden"></div>
  </div>

  <script src="script.js"></script>
</body>
</html>