<?php session_start();?>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>验证码技术登录</title>
</head>
<style>
td{
font-size:9pt;
}
</style>
<script language="javascript">
function check(myform){
if(myform.txt_user.value==""){
alert("请输入用户名!");myform.txt_user.focus();return false;
}
if(myform.txt_pwd.value==""){
alert("请输入密码!");myform.txt_pwd.focus();return false;
}
if(myform.txt_yan.value==""){
alert("请输入验证码!");myform.txt_yan.focus();return false;
}
if(myform.txt_yan.value!=myform.txt_hyan.value){
alert("对不起，您输入的验证码不正确!");myform.txt_yan.focus();return false;
}
}
</script>
<body>
<table width="693" height="346" border="0" align="center" cellpadding="0" cellspacing="0">
<tr>
<td background="images/image_02.png">
<form name="myform" method="post" action="checkuser.php">
<table width="693" border="0" cellspacing="0" cellpadding="0">
<tr>
<td height="42" colspan="5"> </td>
</tr>
<tr>
<td width="154" height="117" rowspan="4"> </td>
<td height="13" colspan="3" align="center" valign="top"> </td>
<td width="160" rowspan="4"> </td>
</tr>
<tr>
<td width="99" height="30" align="right" valign="middle">用户名：</td>
<td colspan="2" align="left" valign="middle"><input type="text" name="txt_user"></td>
</tr>
<tr>
<td height="30" align="right" valign="middle">密 码：</td>
<td height="30" colspan="2" align="left" valign="middle"><input type="password" name="txt_pwd" onCopy="return false" onCut="return false" onPaste="return false" maxlength="60"></td>
</tr>
<tr>
<td height="30" align="right" valign="middle">验证码：</td>
<td width="218" height="32" align="left" valign="middle"><input type="text" name="txt_yan">
<?php
$num=intval(mt_rand(1000,9999));
for($i=0;$i<4;$i++){
echo "<img src=images/checkcode/".substr(strval($num),$i,1).".gif>"; //输出随机的数字图形
}
?>
<input type="hidden" name="txt_hyan" id="txt_hyan" value="<?php echo $num;?>" >
</td>
<td width="62" align="left" valign="middle"><input type="submit" name="Submit" value="登录" onClick="return check(myform);"></td>
</tr>
<tr>
<td height="62" colspan="5"> </td>
</tr>
</table>
</form>
</td>
</tr>
</table>
</body>
</html>