<td class="tdl">所属城市</td>

     <td class="td_detail">

     <input id="sheng" />

     &nbsp<input id="city" />

     &nbsp<input id="xian" />

  </td>

   $("#sheng").combobox({

             url: '../Ajax/Customer.ashx?action=getCityByCode&code=0',

             valueField: 'codeID',

             textField: 'name',

             onLoadSuccess: function () {

             $('#sheng').combobox('select', '---请选择---');

             },

             onChange: function () {

                 var sheng = $("#sheng").combobox("getValue");

                 var tag = ;

                 $("#city").combobox({

                     url: "../Ajax/Customer.ashx?action=getCityByCode&code=" + sheng,

                     valueField: 'codeID',

                     textField: 'name',

                     onLoadSuccess: function () {

                     $('#city').combobox('select', '---请选择---');

                     },

                     onChange: function () {

                         var city = $("#city").combobox("getValue");

                         $("#xian").combobox({

                             url: "../Ajax/Customer.ashx?action=getCityByCode&code=" + city,

                             valueField: 'codeID',

                             textField: 'name',

                             onLoadSuccess: function () {

                             $('#xian').combobox('select', '---请选择---');

                             }

                         })

                     }

                 })

             }

         })