Postback and Autopostback in asp.net

A postback is initiated by the browser, and reloads the whole page, usually when a control on the page (e.g. a button) is changed.

With some controls (e.g. Checkboxes), you choose if changing the control should result in a postback. This property is called AutoPostback.

A callback is initiated by java script in the page, and can load/update parts of the page, e.g. by manipulating the DOM.

Reference
http://stackoverflow.com/questions/3581893/what-is-the-difference-between-postback-autopostback-and-callback[^]