为什么XMLHttpReq.responseText是空的？

[yinyuj2me]

我用ajax做无闪烁刷新页面，结果用alert（XMLHttpReq.responseText）测试，结果为空，为什么XMLHttpReq.responseText是空的？

[孟子E章]

var url = "userInfo.do?action=updateResetMyselfs&id=" + id;


XMLHttpReq.setRequestHeader("Content-Type","application/x-www-form-urlencoded");这行删除，这是无用的


后台
request.getParameter("id")得到id查询数据

[licip]

你单独运行你的发送ajax请求的url看看结果对不对。

[人生无悔]

那就说明后台返回的内容是空的，看下你后台如何返回的，断点到你写的方法

自已创建的XmlHttpRquest一般都写在ashx文件中的

使用ajax服务器控件吧，不用自已写XmlHttpRequest请求了，直接前台页面调用后台方法就好了

[yinyuj2me]

不明白
var XMLHttpReq;
//创建XMLHttpRequest对象
function createXMLHttpRequest() {
if(window.XMLHttpRequest) { //Mozilla 浏览器
XMLHttpReq = new XMLHttpRequest();
}
if (XMLHttpReq.overrideMimeType) {//设置MiME类别
XMLHttpReq.overrideMimeType('text/xml');
}

else if (window.ActiveXObject) { // IE浏览器
try {
XMLHttpReq = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
XMLHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {}
}
}
}
//发送请求函数
function sendRequest() {

createXMLHttpRequest();
var id=document.getElementById("id").value;
var url = "userInfo.do?action=updateResetMyselfs";
XMLHttpReq.open("GET", url, true);

XMLHttpReq.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
XMLHttpReq.setRequestHeader("If-Modified-Since","0");
XMLHttpReq.send(id); // 发送请求
XMLHttpReq.onreadystatechange = processResponse;//指定响应函数
}
// 处理返回信息函数
function processResponse() {
if (XMLHttpReq.readyState == 4) { // 判断对象状态
if (XMLHttpReq.status == 200) { // 信息已经成功返回，开始处理信息

alert(xml);
var xml=XMLHttpReq.responseText;

alert(xml);
document.getElementById("mobilePhone").innerHTML=xml
setInterval("sendRequest()",5000);

} else { //页面不正常
alert("您所请求的页面有异常。");
}
}
}


Action

public String updateResetMyselfs(HttpServletRequest request,
HttpServletResponse response, UserInfoForm userInfoForm, UserInfo uf) {

//response.setContentType("text/xml;charset=utf-8");
// response.setHeader("Cache-Control", "no-cache");
int id = uf.getId();
UserInfoService userInfoService = new UserInfoService();
UserInfo userInfo = userInfoService.getUserInfoById(id);
// ///////////////////////////////////////////////////////
String decPwd = ThreadDes.decryptMode(userInfo.getUserPwd());
userInfoForm.setId(userInfo.getId());
userInfoForm.setUserId(userInfo.getUserId());
userInfoForm.setUserPwd(decPwd);
userInfoForm.setNewUserPwd(decPwd);
userInfoForm.setNewUserPassword(decPwd);
userInfoForm.setUserName(userInfo.getUserName());
userInfoForm.setTelephone(userInfo.getTelephone());
userInfoForm.setMobilePhone(userInfo.getMobilePhone());
String MobilePhone=userInfo.getMobilePhone();
System.out.println(MobilePhone);
return null;
}

[yinyuj2me]

不明白
var XMLHttpReq;
//创建XMLHttpRequest对象
function createXMLHttpRequest() {
if(window.XMLHttpRequest) { //Mozilla 浏览器
XMLHttpReq = new XMLHttpRequest();
}
if (XMLHttpReq.overrideMimeType) {//设置MiME类别
XMLHttpReq.overrideMimeType('text/xml');
}

else if (window.ActiveXObject) { // IE浏览器
try {
XMLHttpReq = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
XMLHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {}
}
}
}
//发送请求函数
function sendRequest() {

createXMLHttpRequest();
var id=document.getElementById("id").value;
var url = "userInfo.do?action=updateResetMyselfs";
XMLHttpReq.open("GET", url, true);

XMLHttpReq.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
XMLHttpReq.setRequestHeader("If-Modified-Since","0");
XMLHttpReq.send(id); // 发送请求
XMLHttpReq.onreadystatechange = processResponse;//指定响应函数
}
// 处理返回信息函数
function processResponse() {
if (XMLHttpReq.readyState == 4) { // 判断对象状态
if (XMLHttpReq.status == 200) { // 信息已经成功返回，开始处理信息

alert(xml);
var xml=XMLHttpReq.responseText;

alert(xml);
document.getElementById("mobilePhone").innerHTML=xml
setInterval("sendRequest()",5000);

} else { //页面不正常
alert("您所请求的页面有异常。");
}
}
}


Action

public String updateResetMyselfs(HttpServletRequest request,
HttpServletResponse response, UserInfoForm userInfoForm, UserInfo uf) {

//response.setContentType("text/xml;charset=utf-8");
// response.setHeader("Cache-Control", "no-cache");
int id = uf.getId();
UserInfoService userInfoService = new UserInfoService();
UserInfo userInfo = userInfoService.getUserInfoById(id);
// ///////////////////////////////////////////////////////
String decPwd = ThreadDes.decryptMode(userInfo.getUserPwd());
userInfoForm.setId(userInfo.getId());
userInfoForm.setUserId(userInfo.getUserId());
userInfoForm.setUserPwd(decPwd);
userInfoForm.setNewUserPwd(decPwd);
userInfoForm.setNewUserPassword(decPwd);
userInfoForm.setUserName(userInfo.getUserName());
userInfoForm.setTelephone(userInfo.getTelephone());
userInfoForm.setMobilePhone(userInfo.getMobilePhone());
String MobilePhone=userInfo.getMobilePhone();
System.out.println(MobilePhone);
return null;
}