[jQuery] Only one of two fields is required. How to implement this logic in Jquery form validation?

[jQuery] Only one of two fields is required. How to implement this logic in Jquery form validation?


There are two input fields in a form, but only one of them is
required, they are not required at the same time. Either A or B is
required. ( A is required OR B is required). In other words, a user
can input data to field A, or he can input data to filed B, but he can
not input data to Both A and B at the same time.
How to implement this constraint in Jquery form validation?