​

​

  $(function() {

        // get the child elements of the dropdown when the DOM has loaded

        var options = $("#theOptions").children('option');

​

        $("input:radio[@name='abc123']").click(function() {         

​

            var radio = $(this).attr('id');   

            var regexEnabled = radio == 'abc' ? /[a-c]/ : /[1-3]/;

​

            // set the option elements in #theOptions to those that match the regular expression

            $("#theOptions").html(

            $(options)

                // filter the option elements to only those we want to include in the dropdown

                .filter( function() { return this.value.match(regexEnabled);})

            );

​

        }); 

​

  });