How to make ajax call from JavaScript ?
Ajax stands for Asynchronous JavaScript and XML. It is used to make asynchronous communication with the server. Ajax is used to read data from the server and update the page or send data to the server without affecting the current client page. Ajax is a programming concept.
Below are some ways to make Ajax call in JavaScript.
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Approach 1: In this approach, we will use the XMLHttpRequest object to make Ajax call. The XMLHttpRequest() method which create XMLHttpRequest object which is used to make request with server.
Syntax:
var xhttp = new XMLHttpRequest();
Above syntax is used to create XMLHttpRequest object. This object has many different methods which are 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:
Javascript
<script> function run() { // Creating Our XMLHttpRequest object var xhr = new XMLHttpRequest(); // Making our connection 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();</script> |
Output:
"{
"userId": 1,
"id": 1,
"title": "delectus aut autem",
"completed": false
}"Approach 2: 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, function to call when we get our response or if error, etc.
Example:
HTML
<!DOCTYPE HTML><html><head> <script src= </script></head><body> <script> function ajaxCall() { $.ajax({ // Our sample url to make request url: // Type of Request type: "GET", // Function to call when to // request is ok success: function (data) { var 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
}Approach 3: 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 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 catch() function to create output for the result. In response, we get the string that we print.
Example:
Javascript
<script> // Url for the request // 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); });</script> |
Output:
{ userId:1 ,id:1 ,title : "delectus aut autem" ,completed : false
__proto__:Object }
Title of our response : delectus aut autem
