Ajax
ELI5 — The Vibe Check
Ajax is the technique of loading data from a server in the background without refreshing the whole page. Before Ajax, clicking 'Load more' would reload the entire page. Now it magically loads new content inline. Ajax is actually an old acronym but the concept is alive and well — we just use Fetch now instead of the original XMLHttpRequest.
Real Talk
Ajax (Asynchronous JavaScript and XML) is a web development technique for asynchronous data exchange between the browser and server without full page reloads. Originally implemented via XMLHttpRequest, modern Ajax uses the Fetch API or libraries like Axios. Despite the name, JSON has replaced XML as the data format.
When You'll Hear This
Infinite scroll is powered by Ajax loading the next batch of posts.,Ajax requests go in the Network tab of DevTools.,Modern Ajax uses Fetch or Axios instead of the original XMLHttpRequest.
Related Terms
Async/Await
Async/await is syntactic sugar that makes Promises look like normal, readable code. Instead of chaining .then().then().
Fetch
Fetch is the modern, built-in JavaScript way to make HTTP requests to APIs. You tell it a URL, it goes and gets the data, and you handle the response.
JSON (JavaScript Object Notation)
JSON is the universal language the internet uses to pass data around. It looks like a JavaScript object — curly braces, key-value pairs.
Promise
A Promise is JavaScript's way of saying 'I'll give you a value eventually — it's not ready yet, but I promise.