jsp中对表单进行初步校验出现的乱码问题，是span区域中出的比如
<span id="usernamespan"></span>
这上面的用javascript校验会回显消息，中文字符出现了乱码；
下面是jsp源码和javascript代码；
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@page contentType="text/html;charset=utf-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>注册页面</title>
</head>
<script type="text/javascript"
src="${pageContext.request.contextPath }/js/register.js">
</script>
<body style="text-align: center; margin: 0px; padding: 0px">
<c:if test="${message==null }">
<div>
<form
action="${pageContext.request.contextPath }/servlet/RegisterServlet"
method="post">
<div>
用户名：
<input type="text" name="username" onblur="checkUsername(this)"
value="${form.username }" />
<span class="message">${form.errors.username }</span>
<span id="usernamespan"></span>
</div>
<br />
<div>
密 码：
<input type="password" name="password" onblur="checkPassword(this)"
value="${form.password }" />
<span class="message">${form.errors.password }</span>
<span id="passwordspan"></span>
</div>
<br />
<div>
确认密码：
<input type="password" name="repassword"
onblur="checkRepassword(this)" value="${form.repassword }" />
<span class="message">${form.errors.repassword }</span>
<span id="repasswordspan"></span>
</div>
<br />
<div>
邮箱：
<input type="text" name="email" onblur="checkEmail(this)" value="${form.email }" />
<span class="message">${form.errors.email }</span>
<span id="emailspan"></span>
</div>
<br />
<div>
生日：
<input type="text" name="birthday" value="${form.birthday }" />
<span class="message">${form.errors.birthday }</span>
</div>
<br />
<div>
昵称：
<input type="text" name="nickname" onblur="checkNickname(this)" value="${form.nickname}" />
<span class="message">${form.errors.nickname }</span>
<span id="nicknamespan"></span>
</div>
<br />
<div>
验证码：
<input type="text" name="checkcode" onblur="checkCheckcode(this)"/>
<img alt="换一张"
src="${pageContext.request.contextPath }/servlet/GenerateImage"
onclick="changeImage(this)" style="cursor: hand" />
<br />
<span class="message">${form.errors.checkcode }</span>
<span id="checkcodespan"></span>
</div>
<br />
<div>
<input type="hidden" name="id" value="${id }" />
<input type="submit" value="注册" />