Answer: ASP.NET AJAX is a set of extensions to ASP.NET for building interactive and responsive web applications. It is used to create dynamic web pages that can update content asynchronously without reloading the entire page, enhancing user experience and performance.
Answer: The main components of ASP.NET AJAX include:
Answer: The ScriptManager control manages client script libraries, partial-page rendering, and web service calls. It must be included on an ASP.NET page to enable AJAX features and can register script files and services that the page will use.
Answer: An UpdatePanel is an ASP.NET AJAX control that allows sections of a web page to be updated asynchronously without a full page refresh. It contains child controls, and only these controls are re-rendered during partial postbacks, improving performance and user experience.
Answer: The UpdateProgress control provides visual feedback to users about the progress of an asynchronous postback, typically displaying a loading message or animation while an update is in progress within an UpdatePanel.
Answer: The Timer control triggers asynchronous postbacks at specified intervals, allowing parts of a page to be updated periodically without user interaction. It is often used to refresh data or update the user interface at regular intervals.
Answer: JSON (JavaScript Object Notation) is a lightweight data-interchange format. In ASP.NET AJAX, JSON is commonly used to exchange data between the client and server in web services, enabling efficient and human-readable communication.
Answer: ASP.NET AJAX includes a client-side JavaScript library (MicrosoftAjax.js) that provides essential functionalities for making asynchronous calls, handling partial page updates, and managing client-side events and controls. It extends the capabilities of JavaScript to work seamlessly with ASP.NET AJAX components.
Answer: You can call a web service from client-side script using the Sys.Net.WebServiceProxy class or the PageMethods feature. By registering the web service with the ScriptManager, you can invoke its methods directly from JavaScript, passing parameters and handling responses asynchronously.
Answer: Synchronous postbacks refresh the entire page, causing a complete reload and potentially disrupting user interaction. Asynchronous postbacks, managed by ASP.NET AJAX, only update specified portions of the page, allowing for a smoother and more responsive user experience by avoiding full page reloads.