I'm using jQuery with the validators plugin. I would like to replace the "required" validator with one of my own. This is easy:

jQuery.validator.addMethod("required", function(value, element, param) {
    return myRequired(value, element, param);
}, jQuery.validator.messages.required);

So far, so good. This works just fine. But what I really want to do is call my function in some cases, and the default validator for the rest. Unfortunately, this turns out to be recursive:

jQuery.validator.addMethod("required", function(value, element, param) {
    // handle comboboxes with empty guids
    if (someTest(element)) {
        return myRequired(value, element, param);
    }
    return jQuery.validator.methods.required(value, element, param);
}, jQuery.validator.messages.required);

I looked at the source code for the validators, and the default implementation of "required" is defined as an anonymous method at jQuery.validator.messages.required. So there is no other (non-anonymous) reference to the function that I can use.

Storing a reference to the function externally before calling addMethod and calling the default validator via that reference makes no difference.

What I really need to do is to be able to copy the default required validator function by value instead of by reference. But after quite a bit of searching, I can't figure out how to do that. Is it possible?

If it's impossible, then I can copy the source for the original function. But that creates a maintenance problem, and I would rather not do that unless there is no "better way."