Progress bar for database query

Ciao,

	i have a seaside application with some user interface.

	Now i have one specific user request for query the database.

	This request required some long time on the server before answer.

	My goal is to : 

		a) display a progress bar when the user submit this query

		b)  block the web user request until the server answer the data query result


	How i can implemented this solution?

	Thank for any considerations.


		Dario