我正在尝试用PHP发送HTML电子邮件，但我无法使代码生效。当标题......
$Headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
...已删除，电子邮件以纯文本形式成功发送。
<?php
$EmailFrom = "***@***.com";
$EmailTo = "***@***.com";
$Subject = "***@***.com";
$Name = trim(stripslashes($_POST['Name']));
$Email = trim(stripslashes($_POST['Email']));
$Message = nl2br(trim(stripslashes($_POST['Message'])));
$ReferredBy = $_POST['referredby'];
$Other = trim(stripslashes($_POST['othertext']));
$Day = $_POST['Day'];
$Month = $_POST['month'];
$Year = $_POST['year'];
if ($Month = 1) {
$Month = 'January';
} elseif ($Month = 2) {
$Month = 'February';
} elseif ($Month = 3) {
$Month = 'March';
} elseif ($Month = 4) {
$Month = 'April';
} elseif ($Month = 5) {
$Month = 'May';
} elseif ($Month = 6) {
$Month = 'June';
} elseif ($Month = 7) {
$Month = 'July';
} elseif ($Month = 8) {
$Month = 'August';
} elseif ($Month = 9) {
$Month = 'September';
} elseif ($Month = 10) {
$Month = 'October';
} elseif ($Month = 11) {
$Month = 'November';
} elseif ($Month = 12) {
$Month = 'December';
}
// prepare email body text
$Body = '<html xmlns="http://www.w3.org/1999/xhtml"><head><title>Thank you for your message!</title><style type="text/css"> @media only screen and (max-width: 647px){#container{padding:0 !important;}#header, #header-content, #body, #content, #info, #body-message{width:100% !important;}#body-message, #quote{padding:20px !important;}} </style></head><body style="margin:0;"><table width="100%" height="100%" style="background-color:#fafafa;font-family:Helvetica Neue, Helvetica, sans-serif;padding:45px;" cellpadding="0" cellspacing="0" id="container"><tr><td><table align="center" cellpadding="0" cellspacing="0" border="0" id="rounded-border-top"><tr><td><img src="http://******.co.uk/email/header.png"/></td></tr></table><table align="center" cellpadding="0" cellspacing="0" border="0" style="border-left:solid 1px #e6e6e6;border-right:solid 1px #e6e6e6;" id="content"><tr><td style="width:600px;background-color:#ffffff;" id="body"><table cellpadding="0" cellspacing="0" border="0" style="padding:45px;color:#303030;line-height:140%;" id="body-message"><tr><td>Hi '.$Name.',<br/><br/> Thank you for your message! I will endeavour to reply to your message within 24 hours. If you have any queries, please feel free to contact me on 07783 962 578.<br/><br/> As a first thanks, here is a free copy of the \'10 top wedding-planning tips\'. It covers the 10 essentials to wedding planning and common mistakes that can be made. Wedding planning is often very stressful, with so many things to think about. So hopefully this little companion will help lessen the load!<br/><br/><a href="downloadfreecopy.html"><img src="http://******.co.uk/email/download_free_copy.png" alt="Download Free Copy" style="border:0;"/></a><br/><br/> Best Wishes,<br/><br/><img src="http://***.co.uk/email/***.png" alt="***"></td></tr></table></td></tr></table><table align="center" cellpadding="0" cellspacing="0" border="0" id="rounded-border-bottom"><tr><td><img src="http://***.co.uk/email/***.png" align="left"></td></tr></table></td></tr></table></body></html>';
$Body2 = '<html xmlns="http://www.w3.org/1999/xhtml"><head><title>Thank you for your message!</title><style type="text/css"> @media only screen and (max-width: 647px){#container{padding:0 !important;}#header, #header-content, #body, #content, #info, #body-message{width:100% !important;}#body-message, #quote{padding:20px !important;}} </style></head><body style="margin:0;"><table width="100%" height="100%" style="background-color:#fafafa;font-family:Helvetica Neue, Helvetica, sans-serif;padding:45px;" cellpadding="0" cellspacing="0" id="container"><tr><td><table align="center" cellpadding="0" cellspacing="0" border="0" id="rounded-border-top"><tr><td><img src="http://******.co.uk/email/header.png"/></td></tr></table><table align="center" cellpadding="0" cellspacing="0" border="0" style="border-left:solid 1px #e6e6e6;border-right:solid 1px #e6e6e6;" id="content"><tr><td style="width:600px;background-color:#ffffff;" id="body"><table cellpadding="0" cellspacing="0" border="0" style="padding:45px;color:#303030;line-height:140%;" id="body-message"><tr><td>New Message<br/><br/><table width="100%" cellpadding="0" cellspacing="10" border="0" style="width:510px;" id="info"><tr><td width="50%"><strong>Question</strong></td><td width="50%"><strong>Answer</strong></td></tr><tr><td>Name:</td><td>'.$Name.'</td></tr><tr><td>Email:</td><td>'.$Email.'</td><tr><td>Phone:</td><td>'.$Telephone.'</td></tr><tr><td>Referred By:</td><td>'.$ReferredBy.'</td></tr><tr><td>Date:</td><td>'.$Day.' '.$Month.' '.$Year.'</td></tr><tr><td colspan="2">Message:<br/><br/><table width="100%" cellpadding="45" cellspacing="0" border="0" style="background-color:#fafafa;color:#505050;font-size:14px;line-height:140%;"><tr><td>'.$Message.'</td></tr></table></td></tr></table></td></tr></table></td></tr></table><table align="center" cellpadding="0" cellspacing="0" border="0" id="rounded-border-bottom"><tr><td><img src="http://******.co.uk/email/rounded_bottom.png" align="left"></td></tr></table></td></tr></table></body></html>';
// prepare email headers
$Headers = 'MIME-Version: 1.0' . "\r\n";
$Headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
$Headers .= 'From: <' . $EmailFrom . '>' . "\r\n";
//Send email to user
mail($Email, $Subject, $Body, $Headers);
// send email to admin
mail($EmailTo, $Subject, $Body2, $Headers);
header("Location: http://******.co.uk/contact-submitted.html");
?>
导致这种情况的原因是什么？