有大神知道easyui 编辑的时候怎么把行数据的id load到form里吗？

<table id="tg" class="easyui-datagrid" width="100%" height="100%"
       data-options="singleSelect:true,url:'{{ URL::to('/') }}/ajson/user',method:'post',loadMsg:'数据请求中!请稍等...',
       toolbar: '#tb',
       pagination:true,
       fit:true
       ">
    <thead>
    <tr>
        <th data-options="field:'id'">编号</th>
        <th data-options="field:'u_id'" formatter = "u_id">用户帐号</th>
        <th data-options="field:'online',align:'center'" formatter="sess">在线</th>
        <th data-options="field:'status',align:'center'" formatter="status">状态</th>
        <th data-options="field:'updated_at',align:'center'">最后登录</th>
        <th data-options="field:'ip',align:'center'">IP</th>
        <th data-options="field:'real',align:'center'" formatter="real">来源</th>
    </tr>
    </thead>
</table>