所以我有以下代码：
索引.html：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Title</title>
</head>
<body>
<form id="form1" name="form1" method="post" action="post.php">
<table width="597" class="formatTblClass">
<tr>
<th colspan="4"></th>
</tr>
<tr><input type="hidden" name="filename" value="example" /></tr>
<tr>
<td width="99"><span>First Name</span></td>
<td width="217"><input class="" type="text" name="firstname" id="firstname" /></td>
<td width="99"><span>Last Name</span></td>
<td width="211"><input class="" name="lastname" type="text" id="lastname" /></td>
<td width="99"><span>Street Address</span></td>
<td width="217"><input class="" type="text" name="streetaddress" id="streetaddress" /></td>
<td width="99"><span>City</span></td>
<td width="211"><input class="" name="city" type="text" id="city" /></td>
<td width="99"><span>State</span></td>
<td width="211"><input class="" name="state" type="text" id="state" /></td>
<td width="99"><span>Phone Number</span></td>
<td width="211"><input class="" name="phone" type="text" id="phone" /></td>
<td width="99"><span>Email</span></td>
<td width="211"><input class="" name="email" type="text" id="email" /></td>
</tr>
<tr>
<td colspan="4">Would you like to receive updates from Company?</td>
</tr>
<tr>
<td colspan="4"><input id="optincompany" name="optincompany" type="checkbox" checked="yes" value="yes" />I want to receive updates from Company.<br /></td>
</tr>
<tr>
<td colspan="4">Would you like to receive updates from Dealer?</td>
</tr>
<tr>
<td colspan="4"><input id="optindealer" name="optindealer" type="checkbox" checked="yes" value="yes" />I want to receive updates from Dealer.<br /></td>
</tr>
<tr>
<td colspan="4">
<div align="center">
<input type="submit" name="Submit" id="Submit" value="Submit" />
<input type="reset" name="Reset" id="button" value="Reset" />
</div></td>
</tr>
</table>
</form>
</body>
</html>
post.php
<?php
$firstname = $_POST['firstname'];
$lastname = $_POST['lastname'];
$streetaddress = $_POST['streetaddress'];
$city = $_POST['city'];
$state = $_POST['state'];
$phone = $_POST['phone'];
$email = $_POST['email'];
//$optindealer = $_POST['optindealer'];
//$optincompany = $_POST['optincompany'];
$optindealer = ( strtolower($_POST['optindealer']) === 'yes' ) ? 'Y' : 'N';
$optincompany = ( strtolower($_POST['optincompany']) === 'yes' ) ? 'Y' : 'N';
$filename = $_POST['filename'] . ".csv";
$today = date("YmdHis");
$fp = fopen($filename, “a”);
$savestring = " " . "," . $today . "," . " " . "," . $firstname . “,” . $lastname . "," . "I" . $address . "," . $city . "," . $state . "," . $optindealer . "," . $today . "," . $phone . "," . $today . "," . $email . “,” . $optincompany . "," . $today;
echo $savestring;
fwrite($fp, $savestring);
fclose($fp);
?>
每当我尝试提交表单时，我都会收到 500 内部服务器错误 ( HTTP Error 500 (Internal Server Error): An unexpected condition was encountered while the server was attempting to fulfill the request.) 而且我不知道为什么。据我所知，我的 php 格式良好，我（绝望地）将目录更改为 777（一旦我弄清楚这里发生了什么，我就会改变它）。有什么建议吗？