AJAX tutorial for beginners in Hindi Part 3: AJAX using JavaScript tutorial in Hindi

Welcome Developers, We will see AJAX tutorial for beginners in Hindi Part 3 - AJAX JavaScript tutorial in Hindi. Get data from servers using ajax javascript. What is AJAX? AJAX = Asynchronous JavaScript And XML. AJAX is not a programming language. AJAX just uses a combination of: A browser built-in XMLHttpRequest object (to request data from a web server) JavaScript and HTML DOM (to display or use the data) AJAX allows web pages to be updated asynchronously by exchanging data with a web server behind the scenes. This means that it is possible to update parts of a web page, without reloading the whole page. How AJAX Works 1. An event occurs in a web page (the page is loaded, a button is clicked) 2. An XMLHttpRequest object is created by JavaScript 3. The XMLHttpRequest object sends a request to a web server 4. The server processes the request 5. The server sends a response back to the web page 6. The response is read by JavaScript 7. Proper action (like page update) is performed by JavaScript The XMLHttpRequest Object All modern browsers support the XMLHttpRequest object. The XMLHttpRequest object can be used to exchange data with a server behind the scenes. This means that it is possible to update parts of a web page, without reloading the whole page. The XMLHttpRequest object is used to exchange data with a server. Send a Request To a Server To send a request to a server, we use the open() and send() methods of the XMLHttpRequest object: GET or POST? GET is simpler and faster than POST, and can be used in most cases. However, always use POST requests when: A cached file is not an option (update a file or database on the server). Sending a large amount of data to the server (POST has no size limitations). Sending user input (which can contain unknown characters), POST is more robust and secure than GET. The onreadystatechange Property The readyState property holds the status of the XMLHttpRequest. The onreadystatechange property defines a function to be executed when the readyState changes. The status property and the statusText property holds the status of the XMLHttpRequest object.