Form validation - Required one of many in a group

Question

In the project I\'m working on at the moment I currently have three textboxes and I need to validate that at least one of the text boxes has been populated.

I\'ve be

Answer 1

It's too late but might be can save some one's time:

If there are only two fields, and want to make one of them required then

If you have three like in question then

If more than this, I will suggest to write a function on scope and watch it.

See the working example