title: jQuery Validate plugin, one field must be empty if another is empty
body: <p>I have a form with multiple address fields. I would like to only allow entry in one field if the previous field has been filled in. I am using jquery validate, and would like to continue to do so. The idea is that although none of these fields are actually required, except the first, you cannot leave gaps in the rest. So if field 3 is blank, you cannot have data in field 4. One way might be to only enable a field when data is entered into the previous, but not sure how to do that in this context.</p>