InfoPath Dev

I have two sharepoint lists :

      1- Department : title

      2- Contacts : FirstName , LastName, Phone , Department(look up Column which is bound to Department list )

so, I have  Designed a form in infopath  which has two dropdown lists , the first one is linked to Department list and I want by changing elements in the first drop down list the  second drop downlist filled by Contacts which are in the selected department

please tell me how is that possible .

Attention : My form Is browser enabled and [filters] are not allowed .   

Thanks alot in advanced .

You can add a filter to the second dropdownlist. Only display the items where the text in department dropdownlist is equal to the department in your secondary datasource.

but filters are not enabled in browser forms .

This can be done.

Their are ways using code but the best is with a dynamic web service.

As you known default secondary data connections return all data and a filter must be used to exclude what is not needed.

This is a showstopper for browser forms and where data sources are large (thousands of records).

Qdabra Database Accelerator includes a web service that you can dynamically query a SQL table.

So you can use the value in the first dropdown in a query for the second. So the data returned is only what matches the first value.