How to make ajax call from JavaScript ?

Ajax is a powerful tool in web development for asynchronous communication with servers. With Ajax, you can fetch data from the server and update your webpage without interrupting what your user sees. It’s a basic concept in programming.

In this article, we’ll learn about three ways to make Ajax calls in JavaScript:

Using the XMLHttpRequest object
Using jQuery
Using fetch() API

We’ll walk through each method with simple examples to help you understand how to use them in your projects.

In this approach, we will use the XMLHttpRequest object to make an Ajax call. The XMLHttpRequest() method creates an XMLHttpRequest object which is used to make a request with the server.

Syntax:

let xhttp = new XMLHttpRequest();

Above syntax is used to create an XMLHttpRequest object. This object has many different methods used to interact with the server to send, receive or interrupt responses from the server. In the response, we get a string from the server that we print.

Example: In this example, we will use the XMLHttpRequest object to make an Ajax call.

Javascript

function run() {

    // Creating Our XMLHttpRequest object 
    let xhr = new XMLHttpRequest();

    // Making our connection  
    let url = 'https://jsonplaceholder.typicode.com/todos/1';
    xhr.open("GET", url, true);

    // function execute after request is successful 
    xhr.onreadystatechange = function () {
        if (this.readyState == 4 && this.status == 200) {
            console.log(this.responseText);
        }
    }
    // Sending our request 
    xhr.send();
}
run();

Output:

"{
  "userId": 1,
  "id": 1,
  "title": "delectus aut autem",
  "completed": false
}"

In this approach, we will use jQuery to make an Ajax call. The ajax() method is used in jQuery to make ajax calls. It is used as a replacement for all approaches which are not working to make ajax calls.

Syntax:

$.ajax({arg1: value, arg2: value, ... });

Parameter: It takes a configuration file that configures the URL, type, and function to call when we get our response or if error, etc.

Example: In this example, we will use jQuery to make an ajax call.

HTML

<!DOCTYPE HTML>
<html>

<head>
    <script src=
"https://code.jquery.com/jquery-3.6.0.min.js">
    </script>
</head>

<body>

    <script>

        function ajaxCall() {
            $.ajax({

                // Our sample url to make request 
                url:
                    'https://jsonplaceholder.typicode.com/todos/1',

                // Type of Request
                type: "GET",

                // Function to call when to
                // request is ok 
                success: function (data) {
                    let x = JSON.stringify(data);
                    console.log(x);
                },

                // Error handling 
                error: function (error) {
                    console.log(`Error ${error}`);
                }
            });
        }
        ajaxCall();
    </script>
</body>

</html>

Output:

{
  "userId": 1,
  "id": 1,
  "title": "delectus aut autem",
  "completed": false
}

In this approach, we will use fetch() API which is used to make XMLHttpRequest with the server. Because of its flexible structure, it is easy to use. This API makes a request to the server and gets the result as a promise which is resolved to the string.

Syntax:

fetch(url, {config}).then().catch();

Parameter: It takes URL and config of the request as parameters.

We will configure the data required and make the request to the server. Since it is a resolved promise we use then() function and the catch() function to create output for the result. In response, we get the string that we print.

Example: In this example, we will use fetch() API to make XMLHttpRequest with the server.

Javascript

// Url for the request 
let url = 'https://jsonplaceholder.typicode.com/todos/1';

// Making our request 
fetch(url, { method: 'GET' })
    .then(Result => Result.json())
    .then(string => {

        // Printing our response 
        console.log(string);

        // Printing our field of our response
        console.log(`Title of our response :  ${string.title}`);
    })
    .catch(errorMsg => { console.log(errorMsg); });

Output:

{ userId:1 ,id:1 ,title : "delectus aut autem" ,completed : false
__proto__:Object }
Title of our response :  delectus aut autem

Approach 1: Using the XMLHttpRequest object

Approach 2: Using jQuery

Approach 3: Using fetch() API

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