You would have to add a Drop Down field to your form that the user would use to select their country. You can use the Bulk Add/Predefined Options on the Drop Down field to populate it with a list of countries.
You can then use Conditional Logic to show or hide fields based on the selection they make in the Select Your Country field that you create as outlined above. You would edit the field, select the advanced tab and enable Conditional Logic and then configure the field and selection that must be made in order for that field to be shown or hidden.
Conditional Logic is mentioned in the documentation for all of the available fields here:
But it's pretty simple. It looks like this: http://i.imgur.com/5rJA7.png
Posted 11 years ago on Tuesday July 19, 2011 | Permalink