求 分析一段代码
JS代码：
[code=JScript]
function GetIsuseInfo(lotteryID) {

currentLotteryID = lotteryID;

try {
//alert(Lottery_Buy_SSC);
Lottery_Buy_SSC.GetIsuseInfo(lotteryID, GetIsuseInfo_callback);


}
catch (e) {

time_GetIsuseInfo = setTimeout( "GetIsuseInfo( " + lotteryID + "); ", 2000);
}
}

function GetIsuseInfo_callback(response) {

if (response == null || response.value == null) {

time_GetIsuseInfo = setTimeout( "GetIsuseInfo( " + currentLotteryID + "); ", 2000);

return;
}

//将time_GetIsuseInfo移除
if (time_GetIsuseInfo != null) {
clearTimeout(time_GetIsuseInfo);
}

var v = response.value;

if (v.indexOf( '| ') == -1) {
return;
}

var arrInfo = v.split( '| ');

if (arrInfo.length != 2) {
return;
}

var currIsuse = arrInfo[0];
var chaseIsuse = arrInfo[1];


$Id( "div_QH_Today ").innerHTML = chaseIsuse;

try {
var firstChase = $Id( "div_QH_Today ").childNodes[0].rows[0].cells[0].childNodes[0];
if (firstChase != undefined) {
firstChase.checked = true;
check(firstChase);
}
} catch (e) { }

var arrcurrIsuse = currIsuse.split( ', ');
$Id( "HidIsuseID ").value = arrcurrIsuse[0];
$Id( "currIsuseName ").innerText = arrcurrIsuse[1];
$Id( "currIsuseEndTime ").innerText = arrcurrIsuse[2].replace( "/ ", "- ").replace( "/ ", "- ");

$Id( "HidIsuseEndTime ").value = arrcurrIsuse[2];

//获取投注时间信息
GetServerTime(currentLotteryID);
}[/code]


Lottery_Buy_SSC.GetIsuseInfo为 后台方法
[code=C#][AjaxMethod(HttpSessionStateRequirement.None)]
public string GetIsuseInfo(int LotteryID)[/code]


问题：
Lottery_Buy_SSC.GetIsuseInfo(lotteryID, GetIsuseInfo_callback);
此处GetIsuseInfo_callback函数调用的时候他的参数 response 是什么意思？


[解决办法]
前台直接调后台 ？ LZ用的DWR？

[解决办法]
response 是后台返回的数据