$j(function() {

             $j("input[id='txtCos']").bind('input propertychange', function () { searchCostCenterbyName($j(this).val()); });

         });

         function searchCostCenterbyName(parameters) {

              $j.ajax({

                 // 调用后台方法方式

                 url: "../../Account/AjaxPage.aspx?method=GetCostCenterContents&corpId="+<%=Corporation%>+"&corpName="+parameters,

                 type: "POST",

                 contentType: "application/json; charset=utf-8",

                 dataType: "json",

                 //解析返回的json数据

                 success: function (dataReturn) {

                     var datar=dataReturn;

                     if (datar.length>0) {

                         $j("#listbCos").empty();

                     }

                     for(var i=0 ;i<datar.length ;i++)

                     {

                          $j("#listbCos").append("<option value=\"" + datar[i].CosID + "\">" +  datar[i].CosName + "</option>");

                     }

                 },

                 error: function () {

                 }

             });

         };

  <td width="28%">

     <input id="txtCos" type="text"  width="100%" />

     <select  id="listbCos"  multiple="Multiple" style="width: 200px; height: 130px;"></select>

  </td>