Chapter 8: Ajax

Question 1

What is AJAX?

Answer 1

A technique for loading data into part of a page without having to refresh the entire page

Question 2

What is JSON?

Answer 2

Javascript Object Notation (Not javascript but string of javascript code)

Question 3

What’s the common syntax for sending an XML Http Request?

xmlhttprequest
XMLHttpRequest
xmlHttpRequest

Answer 3

XMLHttpRequest

Question 4

How to make an AJAX request

Answer 4

-create a new XMLHttpRequest.Then use the open and send methods. The open method takes 3 parameters: HTTP method, URL for page that handles request, Boolean to indicate if it should be asynchronous

var xhr = new XMLHttpRequest();

xhr. open(‘GET’, data/test.json, true);
xhr. send(‘search=arduino’);

Question 5

What happens once the Browser has received and loaded data from the server

Answer 5

The online event will fire. The requests status will be checked and determine what side will run.

xhr.onload = function() {
  if (xhr.status === 200) {
    //do some code
  }
}

Question 6

What Data Formats can the serve send back?

Answer 6

HTML
XML
JSON