[jQuery] use an external js file for validation of many forms

[kathb4]

I want to use an external js file for validation of many forms - all
of which have items in common, like start_date. I want it to be re-
usable from application to application.

Using the groups I have found that I can do this by having something
like
[code]
$(".sharedClassName).each.function() {
  $(this).validate({
    rules: {
      sampling_date: {
        required:           true
       , date:               true
      }
    },
    messages: {
     sampling_date:     "Please enter the date you collected your sample
in the format dd/mm/yyyy."
     }
  });
});
[/code]

BUT I also then want to create validations separately per form using
the rules.add format but I can't seem to make it work. Any ideas where
I am wrong?
[code]
$("input[name^='occurrencer']").rules("add", {
        required:true,
        messages: {
                required: "You must enter a name"
                }
        });
[/code]

Thanks

K