easyui combobox 没有onchange事件，只有onSelect事件
 1 $(function () {

     $('#Select6').combobox({

         onSelect: function (record) {

             var jsonMap = { "year": record.pkey };

             $.ajax({

                 url: "getYearHandler.ashx?action=getdata",

                 type: "post",

                 data: jsonMap,

                 datatype: "json",

                 success: function (data) {

                     var obj = eval('(' + data + ')');

                     dosomething(obj);

                 }

             });

         }

     });

 });