使用JQuery Validation Plugin进行条件验证

I have a simple html form that I've added validation to using the JQuery Validation plugin. I have it working for single fields that require a value. I now need to extend that so that if a user answers Yes to a question they must enter something in the Details field, otherwise the Details field can be left blank. I'm using radio buttons to display the Yes/No. Here's my complete html form - I'm not sure where to go from here:I have a simple html form that I've added valid