Q:

jQuery set value only if empty

I am utilizing a modal for setting a default value for a series of text box fields. However, I only want to set the field to the default value if no value already exists. Is there a way to do that with a jQuery selector?
Current Code
var fooVal = $('#cboxLoadedContent').find('#SetFoo').val();
var barVal = $('#cboxLoadedContent').find('#SetBar').val();
$('.foo').val(fooVal);
$('.bar').val(barVal);

A:

$(".foo[value='']").val(fooVal);

EDIT:
As mentioned by Jonathan if youre using more than text inputs for this youre going to need to be a little more advanced... particularly with select tags, but also checkboxes, radios and textareas. 

