EditFoo

editFoo.js

 editFoo({
    foodentifer: $(this).attr("data-foo");
    newStuffToAdd: {
                         facialHair: "mustache"
                    }, 
    success: function(foo, status, xhr) {
       alert("Foo has a new " + foo.facialHair) // Perhaps prints out "Foo has a new mustache"
       //Or does something like  keeps client + server side in sync after a update operations with a larger JSON payload.
       //x and y actually also have information about the 

      //I use multiple callbacks so I return a JValue object with the "status" field instead so I know what callback to use
    }
});