Hide a subform when selecting a value in a drop down list

Hi,

Do you know how to hide a subform in an interactive form when user select a specific value in a drop down list?

In my forms,I have a drop down list whith 2 values an 2 subforms with different fields . Depending on user selection,

I have to hide the unselected subform.

Do you know how to do this?

Many thanks

Karim