Answer:   Autopostback is the mechanism by which the page will be posted back to the server automatically based on some events in the web controls. In some of the web controls, the property called auto post back, if set to true, will send the request to the server when an event happens in the control.

We will set Autopostback=true when we want to send the request to the server when an event happens in the control.

Answer:   Autopostback is the property of the controls. If you need a control to post back automatically when an event is raised, we need to set the AutoPostBackproperty of the control as True.