<script type=
"text/javascript"
>
function
init(){
document.getElementById(
"username"
).focus();
}
function
validate(userfield) {
if
(trim(userfield.value).length != 0) {
var
xmlHttpRequest =
null
;
var
url =
"../AccountIsExistServlet?account="
+ userfield.value;
var
usermsg = document.getElementById(
"usermsg"
);
if
(window.XMLHttpRequest) {
//表示前浏览器IE
xmlHttpRequest =
new
XMLHttpRequest();
}
else
if
(window.ActiveXObject) {
xmlHttpRequest =
new
ActiveXObject(
"Microsoft.XMLHTTP"
);
}
xmlHttpRequest.open(
"GET"
, url,
true
);
//设置请求式GET设置请求URL设置异步提交
xmlHttpRequest.onreadystatechange =
function
(){
//址复制给onreadystatechange属性
if
(xmlHttpRequest.readyState == 4){
//Ajax引擎状态功
if
(xmlHttpRequest.status == 200){
//HTTP协议状态功
if
(trim(xmlHttpRequest.responseText) !=
""
){
usermsg.innerHTML =
"<font color='red'>"
+ trim(xmlHttpRequest.responseText) +
"</font>"
;
userfield.focus();
}
else
{
usermsg.innerHTML =
"恭喜您用户名使用 "
;
}
}
else
{
alert(
"请求失败错误码="
+ xmlHttp.status);
}
}
};
xmlHttpRequest.send(
null
);
//设置信息发送Ajax引擎
}
else
{
usermsg.innerHTML =
""
;
}
}
<
tr
height
=
"30px;"
>
<
td
><
font
color
=
"#FF0000"
>*</
font
>用户名：</
td
>
<
td
><
input
type
=
"text"
name
=
"account"
id
=
"username"
maxlength
=
"12"
onblur
=
"validate(this)"
/></
td
>
<
td
width
=
"220px;"
><
span
id
=
"usermsg"
></
span
></
td
>
</
tr
>
|
import
java.io.IOException;
import
java.io.PrintWriter;
import
javax.servlet.ServletException;
import
javax.servlet.annotation.WebServlet;
import
javax.servlet.http.HttpServlet;
import
javax.servlet.http.HttpServletRequest;
import
javax.servlet.http.HttpServletResponse;
import
com.gas.bo.UserInfoBO;
@WebServlet
(
"/AccountIsExistServlet"
)
public
class
AccountIsExistServlet
extends
HttpServlet {
protected
void
doGet(HttpServletRequest request,
HttpServletResponse response)
throws
ServletException, IOException {
// 阻止缓存
response.setContentType(
"text/xml"
);
response.setHeader(
"Cache-Control"
,
"no-store"
);
// HTTP1.1
response.setHeader(
"Pragma"
,
"no-cache"
);
// HTTP1.0
response.setDateHeader(
"Expires"
,
0
);
// prevents catching at proxy
// server
PrintWriter out = response.getWriter();
//js传汉字进行转码避免汉字候现乱码
String account = request.getParameter(
"account"
);
UserInfoBO userInfoBO =
new
UserInfoBO();
boolean
b = userInfoBO.accountIsExist(account);
if
(b) {
out.print(
"用户名已存请重新输入"
);
}
}
}