XMLHttpRequest RESTful (GET, POST, PUT, DELETE)

user.js

// Get all users
var url  = "http://localhost:8080/api/v1/users";
var xhr  = new XMLHttpRequest()
xhr.open('GET', url, true)
xhr.onload = function () {
	var users = JSON.parse(xhr.responseText);
	if (xhr.readyState == 4 && xhr.status == "200") {
		console.table(users);
	} else {
		console.error(users);
	}
}
xhr.send(null);


// Get a user
var url  = "http://localhost:8080/api/v1/users";
var xhr  = new XMLHttpRequest()
xhr.open('GET', url+'/1', true)
xhr.onload = function () {
	var users = JSON.parse(xhr.responseText);
	if (xhr.readyState == 4 && xhr.status == "200") {
		console.table(users);
	} else {
		console.error(users);
	}
}
xhr.send(null);


// Post a user
var url = "http://localhost:8080/api/v1/users";

var data = {};
data.firstname = "John";
data.lastname  = "Snow";
var json = JSON.stringify(data);

var xhr = new XMLHttpRequest();
xhr.open("POST", url, true);
xhr.setRequestHeader('Content-type','application/json; charset=utf-8');
xhr.onload = function () {
	var users = JSON.parse(xhr.responseText);
	if (xhr.readyState == 4 && xhr.status == "201") {
		console.table(users);
	} else {
		console.error(users);
	}
}
xhr.send(json);


// Update a user
var url = "http://localhost:8080/api/v1/users";

var data = {};
data.firstname = "John2";
data.lastname  = "Snow2";
var json = JSON.stringify(data);

var xhr = new XMLHttpRequest();
xhr.open("PUT", url+'/12', true);
xhr.setRequestHeader('Content-type','application/json; charset=utf-8');
xhr.onload = function () {
	var users = JSON.parse(xhr.responseText);
	if (xhr.readyState == 4 && xhr.status == "200") {
		console.table(users);
	} else {
		console.error(users);
	}
}
xhr.send(json);


// Delete a user
var url = "http://localhost:8080/api/v1/users";
var xhr = new XMLHttpRequest();
xhr.open("DELETE", url+'/12', true);
xhr.onload = function () {
	var users = JSON.parse(xhr.responseText);
	if (xhr.readyState == 4 && xhr.status == "200") {
		console.table(users);
	} else {
		console.error(users);
	}
}
xhr.send(null);

At line 44 why 201 instead of 200? Is it a mistake or intentional???

When um post a file, the answer is 201 (created). It means the file was created successfully in the server.

thank you

Hi team,
from LN: 31 to 50 i.e. for Post a user, at xhr.onload = function () {} there is asynchronous call so might be control is not reaching at var users = JSON.parse(xhr.responseText); line.
Please guide me here..
Thank You!

Surbhi Rathi

Thanks a lot! It was quite helpful to me:)

You are the best. God bless you :))

Great! thank you.

Thank you :)

This is a great reference. Thanks very much for posting.

Excellent!