AutoCalculating No. of days in a text box, according to the date range chosen from 2 AJAX calendars (From & To)

Hi Friends,
I'm looking for a solution of the following simple requirement for an ASP.Net 2.0 based website. Not sure whether the best solution is in C# or Javascript. Anything will do.
I've 3 textboxes on a form. 1st and 2nd textboxes are associated with a AJAX calendar control. As soon we choose the dates (FROM & TO) from the 2 calendars into the respective textboxes, the 3rd textbox should calculate the number of days from those given dates.
How can we do that? I need it urgently.
 
Thanks for your help.
Mohit

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