js and ajax process the json object returned by the java background

//注：LO是表格的id； 需要自己创建表头， n行，9列的表格；
var tab_id;
function varify(cardinno) {
tab_id=document.getElementById("Layer1");
displayp();
tab_id.style.display="none";
var url="getRefInfoServlet?cardInNo="+cardinno;
var myAjax=new Ajax.Request(url,{method:'post', parameters:'0', onSuccess:doOnComplete, asynchronous:true});
}
var doOnComplete=function(xml_httpRequest){
var msg=eval(xml_httpRequest.responseText);
var info=msg.length;
var row;
var col;
if(info>0)
{
for(var i=0;i<info;i++){
row = L0.insertRow(L0.rows.length);
row.insertCell(0).innerHTML =" "+msg[i].a;
row.insertCell(1).innerHTML =" "+msg[i].b;
row.insertCell(2).innerHTML =" "+msg[i].c;
row.insertCell(3).innerHTML =" "+msg[i].d;
row.insertCell(4).innerHTML =" "+msg[i].e;
row.insertCell(5).innerHTML =" "+msg[i].f;
row.insertCell(6).innerHTML =" "+msg[i].g;
row.insertCell(7).innerHTML =" "+msg[i].h;
row.insertCell(8).innerHTML =" "+msg[i].i;
row.setAttribute("align", "center");
}
tab_id.style.display="block";
}else{
tab_id.innerHTML="<center>抱歉，该卡未开通，获取不到租还车信息！</center>";
tab_id.style.width = "80%";
  tab_id.style.position = "absolute";//绝对位置显示
tab_id.style.display="block";
}
removep();
}
//遮罩层显示
displayp=function()
{
  var mybg = document.createElement("p");
  mybg.setAttribute("id","mybg");
  mybg.innerHTML="<center>正在处理中, 请稍候<img src=&#39;lib/images/loading.gif&#39;></img></center>";
  mybg.style.width = "100%";
  mybg.style.position = "absolute";//绝对位置显示
  mybg.style.top = "260";
  mybg.style.left = "0";
  mybg.style.zIndex = "100";//z轴位置
  mybg.style.opacity = "0.8";//透明度
  mybg.style.filter = "Alpha(opacity=80)";//滤镜显示透明度
  document.body.appendChild(mybg);
}
//遮罩层移除
removep=function()
{
document.body.removeChild(mybg);
}

/**
* 根据卡内码得到最近的租还车记录
* 返回json对象
* @param cardInNo
* @return
*/
public String getRefInfo(String cardInNo)
{
StringBuffer bf=new StringBuffer(1024);
bf.append("");//sql语句
System.out.println(bf.toString());
/************ 存储json对象***************/
List<JSONObject> jsonList=new ArrayList<JSONObject>();
    try {
    /****************获得判断信息存入数组中*******************/
    String [][] str=getArrayByName(bf.toString());
    if(str!=null){
    for (int i = 0; i < str[0].length; i++) {
    JSONObject returnValue =new JSONObject();
    returnValue.put("a", str[0][i])
    .put("b", str[1][i])
    .put("c", str[2][i].trim().equals("")?"":str[2][i].substring(0, 19))
    .put("d", str[3][i].trim().equals("")?"":str[3][i].substring(0, 19))
    .put("e", str[4][i])
    .put("f", str[5][i])
    .put("g", str[6][i])
    .put("h", str[7][i])
    .put("i", str[8][i]);
    jsonList.add(returnValue);
    }
  }
}catch (Exception e) {
e.printStackTrace();
}
System.out.println(jsonList.toString());
return jsonList.toString();
}