如何将dwr回调函数得来的数据用extjs如何循环输出啊！

<SCRIPT type="text/javascript" language="javascript">
ManualSignBiz.loadAll(show); 
function show(manualSignList){
for (var index = 0; index < manualSignList.length; index++) {
var id   = manualSignList[index].signId;
var user = manualSignList[index].userinfo.userName;
var time = manualSignList[index].singTime;
var desc = manualSignList[index].signDesc;
var tag  = manualSignList[index].singTag;


var store =new Ext.data.JsonStore({data:data,fields:["id","user","time","desc","tag"]});
var colM =new Ext.grid.ColumnModel([
{header:"姓名",dataIndex:"user",renderer:showUrl, sortable:true},
{header:"性别",dataIndex:"time",renderer:showName,sortable:true},
{header:"年龄",dataIndex:"desc",sortable:true},
{header:"工资",dataIndex:"tag",renderer:'usMoney',sortable:true}
]);
var grid=new Ext.grid.GridPanel({
renderTo:"hello",
title:"学员表",
width:600,
height:200,
cm:colM,
store:store,
autoExpandColumn:2
    });
}
</SCRIPT>