Introduction to MDN Browser Compatibility Data
The MDN Browser Compatibility Data (BCD) is an essential resource for web developers, providing comprehensive data on the support of web features across different browsers. This dataset is invaluable for ensuring cross-browser compatibility and smooth user experiences. In this guide, we delve into the BCD and explore some key APIs with examples to enhance your web development skills.
Using the localStorage API
The localStorage API allows you to store data on the client’s browser without an expiration time. This data persists even when the browser is closed and reopened.
// Storing data localStorage.setItem('username', 'JohnDoe');
// Retrieving data const username = localStorage.getItem('username'); console.log(username); // Outputs 'JohnDoe'
// Removing data localStorage.removeItem('username'); Working with the fetch API
The fetch API provides a simple interface for making HTTP requests and handling responses.
// Making a simple GET request fetch('https://api.example.com/data') .then(response => response.json()) .then(data => console.log(data)) .catch(error => console.error('Error:', error)); Exploring the IntersectionObserver API
The IntersectionObserver API allows you to monitor the visibility of elements within a container or viewport, making it useful for lazy-loading images or infinite scrolling.
const observer = new IntersectionObserver((entries) => { entries.forEach(entry => { if (entry.isIntersecting) { entry.target.src = entry.target.dataset.src; observer.unobserve(entry.target); } }); });
document.querySelectorAll('img').forEach(img => { observer.observe(img); }); Building an App with These APIs
Let’s build a simple app using localStorage, fetch, and the IntersectionObserver APIs. Our app will store user preferences, fetch data from an API, and lazy-load images.
<!DOCTYPE html> <html lang='en'> <head> <meta charset='UTF-8'> <meta name='viewport' content='width=device-width, initial-scale=1.0'> <title>Simple App</title> </head> <body>
<h1>Simple App</h1>
<h2>User Preference</h2> <input type='text' id='username-input' placeholder='Enter your username'> <button id='save-btn'>Save Username</button> <p id='display-username'></p>
<h2>Data Fetching</h2> <button id='fetch-btn'>Fetch Data</button> <pre id='data-output'></pre>
<h2>Lazy-Load Images</h2> <img data-src='https://via.placeholder.com/150' alt='Lazy Load Example'> <img data-src='https://via.placeholder.com/150' alt='Lazy Load Example'>
<script> // localStorage API const saveBtn = document.getElementById('save-btn'); const usernameInput = document.getElementById('username-input'); const displayUsername = document.getElementById('display-username');
saveBtn.addEventListener('click', () => { const username = usernameInput.value; localStorage.setItem('username', username); displayUsername.innerText = 'Username: ' + username; });
document.addEventListener('DOMContentLoaded', () => { const savedUsername = localStorage.getItem('username'); if (savedUsername) { displayUsername.innerText = 'Username: ' + savedUsername; } });
// fetch API document.getElementById('fetch-btn').addEventListener('click', () => { fetch('https://api.example.com/data') .then(response => response.json()) .then(data => { document.getElementById('data-output').innerText = JSON.stringify(data, null, 2); }) .catch(error => console.error('Error:', error)); });
// IntersectionObserver API const observer = new IntersectionObserver((entries) => { entries.forEach(entry => { if (entry.isIntersecting) { entry.target.src = entry.target.dataset.src; observer.unobserve(entry.target); } }); });
document.querySelectorAll('img').forEach(img => { observer.observe(img); }); </script> </body> </html> With these examples, you can see how powerful and versatile the MDN Browser Compatibility Data can be for building robust web applications.
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