easyui combobox input 下拉框 加入默认值

<td>
                        <input id="textdefaut" class="easyui-combobox"  data-options="
                                        url:'/Wx/Get2ComboList',
                                        queryParams:{'group':'BianLiangType'},
                                        valueField:'value',
                                        height:30,
                                        editable:false,
                                        textField:'text',
                                        required:true,
                            onLoadSuccess: function(data){defaut1()}" style="width: 300px"/>
                    </td><td>
                        <input id="