Send asynchronous browser requests with fetch, XMLHttpRequest, JSON, errors, and progressive UI.
Lessons
Use the Network tab to inspect requests and responses.
Debugging AJAX is easiest to learn by reading the example, changing it, and observing the result.
// Open DevTools -> Network tab to inspect each request:
// - Status code, method, and timing
// - Request headers and payload
// - Response headers and body
const res = await fetch('/api/lessons');
console.log('Status:', res.status);
console.log('Body:', await res.clone().json()); // clone so the body can be read againPractice the Debugging AJAX example in a small scratch file, then explain what changed and why.