PHP邮件函数html内容在电子邮件中不可见

我正在尝试使用php mail（）函数发送带有附件的电子邮件。已正确发送带有附件的电子邮件，但html内容（邮件正文）在我的电子邮件中不可见。它只显示附件文件

<?php
$htmlbody="
<strong>Name:</strong> {$_POST['name']}<br>
<strong>Position:</strong> {$_POST['position']}<br>
<strong>Email:</strong> {$_POST['email']}<br>
<strong>Phone:</strong> {$_POST['phone']}<br>
<strong>Date Of Birth:</strong> {$_POST['dob']}<br>
<strong>Qualification:</strong> {$_POST['qual']}<br>
<strong>Experiance:</strong> {$_POST['experiance']}<br>
<strong>Remarks:</strong> {$_POST['remarks']}";

$strSid = md5(date('r', time()));
$strHeader = "";  
$strHeader .= "From: {$_POST['email']}\nReply-To: {$_POST['email']}\n";
$strHeader .= "MIME-Version: 1.0\n";  
$strHeader .= "Content-Type: multipart/mixed; boundary=\"".$strSid."\"\n";  
$strHeader .= "This is a multi-part message in MIME format.\n";  
$strHeader .= "--".$strSid."\n";  
$strHeader .= "Content-type: text/html; charset=utf-8\n";  
$strHeader .= "Content-Transfer-Encoding: 7bit\n";  
$strHeader .= "Content: ".$htmlbody."\n";

//*** Attachment ***//  
if(isset($_FILES['resume'])){
    $filename = $_FILES['resume']['name'];
    $ext = pathinfo($filename,PATHINFO_EXTENSION);

    if(!in_array($ext,array('doc','docx'))){ die('Invalid File'); }

    move_uploaded_file($_FILES['resume']['tmp_name'],"temp/$filename");
    $strContent = chunk_split(base64_encode(file_get_contents("temp/$filename")));

    $strHeader .= "--".$strSid."\n";  
    $strHeader .= "Content-Type: application/octet-stream; name=\"".$filename."\"\n";  
    $strHeader .= "Content-Transfer-Encoding: base64\n";  
    $strHeader .= "Content-Disposition: attachment; filename=\"".$filename."\"\n";
}

$to = "name@domain.com";
$subject = "Test email with attachment";
$mail = mail($to, $subject, $htmlbody, $strHeader);    
echo $mail ? "Mail sent" : "Mail failed";
?>

---

只是删除“
$strHeader.=”这是一个MIME格式的多部分消息。\n“
”并将“
$strHeader.=”内容：“..$htmlbody.”\n“
”替换为“
$strHeader.=”$htmlbody.\n”“
尝试将其包装在
标签中？@Epodax:什么都没发生，伙计。。。