代码如下
<span style="font-size:18px;"><%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<script type="text/javascript" src="js/jQuery.js"></script>
<script type="text/javascript" src="js/verifyCode.js"></script>
<title>java验证码</title>
</head>
<body>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td width="100"> </td>
<td width="70">验证码：</td>
<td width="150"><input id="veryCode" name="veryCode" type="text" class="yanzma" value="" onmouseout="isRightCode()"/></td>
<td width="135"><img id="imgObj" alt="" src="DrawImage" /></td>
<td><a href="#" onclick="changeImg()">换一张</a></td>
<td></td>
</tr>
<tr>
<td style="line-height: 38px; color: #FF0000; text-align: center;" colspan="4" id="info"> </td>
<td></td>
</tr>
</table>
</body>
</html>
</span>原文：http://blog.csdn.net/wenzhilanyu2012/article/details/41279023