It slims down everything and datepicker params as well. This matcher:

    $(@).find(':input[value=""]')

match all date-related params, even if they aren't empty. I tried it in console and found out, this selector match all date-related attributes. But if I try to find some attribute via jQuery directly:

    $("#create_at_field).value

provide me with correct value. We use jQuery 1.9.1.
Does it correctly filter by created_at/update_at attributes in your case?