easyui combobox 带 checkbox

$('#cc').combobox({                url:'combobox_data1.json',                method:'get',                valueField:'id',                textField:'text',                panelHeight:'auto',                multiple:true,                formatter: function (row) {                    var opts = $(this).combobox('options');                    return '<input type="checkbox" class="combobox-checkbox">' + row[opts.textField]                },                onLoadSuccess: function () {                    var opts = $(this).combobox('options');                    var target = this;                    var values = $(target).combobox('getValues');                    $.map(values, function (value) {                        var el = opts.finder.getEl(target, value);                        el.find('input.combobox-checkbox')._PRopAttr('checked', true);                    })                },                onSelect: function (row) {                    //console.log(row);                    var opts = $(this).combobox('options');                    var el = opts.finder.getEl(this, row[opts.valueField]);                    el.find('input.combobox-checkbox')._propAttr('checked', true);                },                onUnselect: function (row) {                    var opts = $(this).combobox('options');                    var el = opts.finder.getEl(this, row[opts.valueField]);                    el.find('input.combobox-checkbox')._propAttr('checked', false);                }            });