jQuery ajax to get staff from selected department

jquery_ajax.js

            $(document).ready(function(){
                $date_from = $('#date_from').val();$date_to = $('#date_to').val();$source = '';
                $('#teamSelector').change(function(){
                    $selected_team = $(this).val();
                    $.ajax({
                        url : $baseUrl + "/public/staff/staff/return-json-staff",
                        type : "POST",
                        data : 'selected_team='+$selected_team+'&date_from='+$date_from+'$date_to='+$date_to+'&source='+$source
                    }).done(function($response){
                        var obj = jQuery.parseJSON($response);
                        $element = $('<select name="staff" id="staff">');
                        $element.append('<option value="all"></option>');
                        for(var x in obj){
                            console.log(x)
                            $element.append('<optgroup label="' + x + '">');
                             for(var y in obj[x]){
                                 $element.append('<option value="' + y + '">' + obj[x][y] + '</option>')
                             }
                            $element.append('</optgroup>');
                        }
                        $element.append('</select>');
                        $('#staffSelectContainer').html($element);
                    })
                })
            })