EasyUI_前台js_省市县三级联动

1、html:

  <td class="tdl">所属城市</td>
     <td class="td_detail">
     <input id="sheng" />
     &nbsp<input id="city" />
     &nbsp<input id="xian" />
  </td>

2、js

   $("#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---');
                             }
                         })
                     }
                 })
             }
         })