PHP-->jquery esayui获取json失败

 1 <table class="easyui-datagrid" style="width:600px;height:250px"
 2             url="data/datagrid_data.json"
 3             title="DataGrid - Complex Toolbar" toolbar="#tb"
 4             singleSelect="true" fitColumns="true">
 5         <thead>
 6             <tr>
 7                 <th field="field1" width="60">xxx</th>
 8                ........
 9                 <th field="field2" width="60">xxx</th>
10             </tr>
11         </thead>
12     </table