UltimateCallback is an ASP.NET server control to provide callback functionality in your web applications. This control allows you to make web pages more responsive by exchanging data with the server behind the scenes. Every time the user initiates a callback request UltimateCallback control refreshes only its own contents instead of reloading the entire web page as in the case of a regular postback to server. * AJAX - AJAX (Asynchronous JavaScript And XML) enable your web applications to increase interactivity, speed and usability. * Drag-Drop - Drag and drop HTML and ASP.NET controls into the UltimateCallback panel. * Callback Result - Return callback result to a client-side function instead of rendering. * Callback Error - Return callback error to a client-side function for exception handling. * Loading Display - Display an HTML block while processing the callback request. * Enable Caching - Cache callback arguments and results on the client-side to improve performance. * Save State - Get the latest state of all form elements with the callback request. * Auto Callback - Initiate callbacks automatically at specified intervals in milliseconds. * Override Output - Override the callback contents both on the server-side and client-side. * Down Level Browser Support - Handle callback requests as regular postbacks when XmlHttp is not supported. * Client-Side API - Initiate callback requests and pass arguments to server. * Server-Side API - Process callback request in the Callback event handler.