jqGridフォーム編集で依存する選択ボックスを動的に更新するにはどうすればよいですか?

var countries = { '1': 'US', '2': 'UK' };
var states = { '1': 'Alabama', '2': 'California', '3': 'Florida', '4': 'Hawaii', '5': 'London', '6': 'Oxford' };
var statesOfCountry = {
    1: { '1': 'Alabama', '2': 'California', '3': 'Florida', '4': 'Hawaii' },
    2: { '5': 'London', '6': 'Oxford' }
};
var mydata = [
    { id: '0', Country: '1', State: '1', Name: "Louise Fletcher" },
    { id: '1', Country: '1', State: '3', Name: "Jim Morrison" },
    { id: '2', Country: '2', State: '5', Name: "Sherlock Holmes" },
    { id: '3', Country: '2', State: '6', Name: "Oscar Wilde" }
];

var lastSel = -1;
var grid = jQuery("#list");
var resetStatesValues = function () {
    grid.setColProp('State', { editoptions: { value: states} });
};
grid.jqGrid({
    data: mydata,
    datatype: 'local',
    colModel: [
        { name: 'Name', width: 200 },
        { name: 'Country', width: 100, editable: true, formatter: 'select',
            edittype: 'select', editoptions: {
                value: countries,
                dataInit: function (elem) {
                    var v = $(elem).val();
                    grid.setColProp('State', { editoptions: { value: statesOfCountry[v]} });
                },
                dataEvents: [
                    {
                        type: 'change',
                        fn: function(e) {
                            // Update 'State' options based on the selected 'Country' value
                            var v = parseInt($(e.target).val(), 10);
                            var sc = statesOfCountry[v];
                            var newOptions = '';
                            for (var stateId in sc) {
                                newOptions += '<option role="option" value="' +
                                                   stateId + '">' +
                                                   states[stateId] + '</option>';
                            }

                            // Populate the new options
                            if ($(e.target).is('.FormElement')) {
                                // Form editing
                                var form = $(e.target).closest('form.FormGrid');
                                $("select#State.FormElement", form[0]).html(newOptions);
                            } else {
                                // Inline editing
                                var row = $(e.target).closest('tr.jqgrow');
                                var rowId = row.attr('id');
                                $("select#" + rowId + "_State", row[0]).html(newOptions);
                            }
                        }
                    }
                ]
            }
        },
        {
            name: 'State', width: 100, editable: true, formatter: 'select',
            edittype: 'select', editoptions: { value: states }
        }
    ],
    onSelectRow: function (id) {
        // Handler to maintain row selection and reset 'State' values
        if (id &amp;&amp; id !== lastSel) {
            if (lastSel != -1) {
                resetStatesValues();
                grid.restoreRow(lastSel);
            }
            lastSel = id;
        }
    },
    ondblClickRow: function (id) {
        // Handler for double-click editing
        if (id &amp;&amp; id !== lastSel) {
            grid.restoreRow(lastSel);
            lastSel = id;
        }
        resetStatesValues();
        grid.editRow(id, true, null, null, 'clientArray', null,
                         function (rowid, response) {  // aftersavefunc
                            grid.setColProp('State', { editoptions: { value: states} });
                         });
        return;
    },
    editurl: 'clientArray',
    sortname: 'Name',
    height: '100%',
    viewrecords: true,
    rownumbers: true,
    sortorder: "desc",
    pager: '#pager',
    caption: "Demonstrate dependend select/dropdown lists (edit on double-click)"
}).jqGrid('navGrid','#pager', 
           { edit: true, add: true, del: false, search: false, refresh: false },
           { // edit options
               recreateForm:true,
               onClose:function() {
                   resetStatesValues();
               }
           },
           { // add options
               recreateForm:true,
               onClose:function() {
                   resetStatesValues();
               }
           });