AJAX & Promise & Fetch API
- AJAX stands for Asynchronous JavaScript and XML.
- AJAX is not a technology in itself, but the use of XMLHttpRequest to communicate with servers.
- Using AJAX, we can update web pages asynchronously, meaning updating parts of a page without reloading the whole page.
- This concept allows apps to be faster and more responsive to user actions.
- By creating a XMLHttpRequest object which manages a request, it sends a request to the server, awaits for the response, and invokes a callback function.
- In contrast, Synchronous means loading the new page and temporarily making the browser window blank, so that the client has to wait for the server to respond.
- We first create an XMLHttpRequest object, which will tell the request object which function will handle the response using the traditional method.
- Using the open() and send() method, we can actually make a request to the server.
- If we decided to use the POST method instead of GET method, we can send any data to the server using the send() method.
- After checking the request's state at the callback function and the HTTP response status, we get to do whatever we want with the data the server sent.
- Using JSON.parse(), we change the response into a object.
- XML and jQuery are outdataed technologies that do similar roles.