jQuery.fn.filterOn = function(selection, values) {

        return this.each(function() {

            var select = this;

            var options = [];

            $(select).find('option').each(function() {

                options.push({value: $(this).val(), text: $(this).text()});

            });

            $(select).data('options', options);

            $(selection).change(function(){

        $(selection + " option:selected").each(function(){

          var options = $(select).empty().data('options');

          var haystack = values[$(this).attr('id')];    

          $.each(options, function(i){

            var option = options[i];

            if($.inArray(option.value, haystack) !== -1) {

                        $(select).append(

                        $('<option>').text(option.text).val(option.value)

                        );

                    }

          });

        });

      });

        });

    };

​

​

$(document).ready(function(){

  $(function() {

        $('#SecondStage').filterOn('#FirstStage', {

            'A': ['value-A-aaa','value-A-bbb','value-ccc','value-A-ddd','value-A-eee','z'],

          'B': ['value-B-xxx','value-B-yyy','value-B-zzz','0']   

        });

      return true;

  });

  });