Send asynchronous browser requests with fetch, XMLHttpRequest, JSON, errors, and progressive UI.
Lessons
Learn how asynchronous JavaScript and XML evolved into modern fetch.
What Is AJAX is easiest to learn by reading the example, changing it, and observing the result.
async function loadLessons() {
const response = await fetch('/api/lessons', {
headers: { 'Accept': 'application/json' }
});
if (!response.ok) {
throw new Error(`HTTP ${response.status}`);
}
return response.json();
}
loadLessons()
.then(lessons => console.log(lessons))
.catch(error => console.error('Failed to load:', error.message));Practice the What Is AJAX example in a small scratch file, then explain what changed and why.