Q:

PHP mail() attachment problems

Can someone help me figure out why this keeps returning false? 
$to = "myemail@mydomain.com";
$from = "Website <website@mydomain.com>";
$subject = "Test Attachment Email";

$separator = md5(time());

// carriage return type (we use a PHP end of line constant)
$eol = PHP_EOL;

// attachment name
$filename = "document.pdf";

//$pdfdoc is PDF generated by FPDF
$attachment = chunk_split(base64_encode($pdfdoc));

// main header
$headers  = "From: ".$from.$eol;
$headers .= "MIME-Version: 1.0".$eol; 
$headers .= "Content-Type: multipart/mixed; boundary=\"".$separator. "\"".$eol.$eol; 
$headers .= "Content-Transfer-Encoding: 7bit".$eol;
$headers .= "This is a MIME encoded message. ".$eol.$eol;

// message
$headers .= "--".$separator.$eol;
$headers .= "Content-Type: text/html; charset=\"iso-8859-1\"".$eol;
$headers .= "Content-Transfer-Encoding: 8bit".$eol.$eol;
$headers .= $message.$eol.$eol;

// attachment
$headers .= "--".$separator.$eol;
$headers .= "Content-Type: application/octet-stream; name=\"".$filename. "\"".$eol; 
$headers .= "Content-Transfer-Encoding: base64".$eol;
$headers .= "Content-Disposition: attachment".$eol.$eol;
$headers .= $attachment.$eol.$eol;
$headers .= "--".$separator."--"; 

// send message
if (mail($to, $subject, "", $headers)) {
    echo "mail send ... OK";
} else {
    echo "mail send ... ERROR";
}

A:

$to = "myemail@mydomain.com";
$from = "Website <website@mydomain.com>";
$subject = "Test Attachment Email";

$separator = md5(time());

// carriage return type (we use a PHP end of line constant)
$eol = PHP_EOL;

// attachment name
$filename = "document.pdf";

//$pdfdoc is PDF generated by FPDF
$attachment = chunk_split(base64_encode($pdfdoc));

// main header
$headers  = "From: ".$from.$eol;
$headers .= "MIME-Version: 1.0".$eol; 
$headers .= "Content-Type: multipart/mixed; boundary=\"".$separator."\""; 

// no more headers after this, we start the body! // 

$body = "--".$separator.$eol;
$body .= "Content-Transfer-Encoding: 7bit".$eol.$eol;
$body .= "This is a MIME encoded message. ".$eol;

// message
$body .= "--".$separator.$eol;
$body .= "Content-Type: text/html; charset=\"iso-8859-1\"".$eol;
$body .= "Content-Transfer-Encoding: 8bit".$eol.$eol;
$body .= $message.$eol;

// attachment
$body .= "--".$separator.$eol;
$body .= "Content-Type: application/octet-stream; name=\"".$filename. "\"".$eol; 
$body .= "Content-Transfer-Encoding: base64".$eol;
$body .= "Content-Disposition: attachment".$eol.$eol;
$body .= $attachment.$eol;
$body .= "--".$separator."--"; 

// send message
if (mail($to, $subject, $body, $headers)) {
    echo "mail send ... OK";
} else {
    echo "mail send ... ERROR";
}

What I've done:

Separated the body from the headers
removed extra EOLs put before separators

A:

I was also facing issue and found a neat answer.  You can use this function for multiple attachment. 
function mail_attachment($files, $path, $mailto, $from_mail, $from_name, $replyto, $subject, $message, $cc, $bcc) 
{
    $uid = md5(uniqid(time()));
    $header = "From: ".$from_name."  <".$from_mail. ">\r\n";
    $header .= "Reply-To: ".$replyto. "\r\n";
    $header .= "cc : < $cc > \r\n" ;  // comma saparated emails
    $header .= "Bcc :  < $bcc >\r\n"; // comma saparated emails
    $header .= "MIME-Version: 1.0\r\n";
    $header .= "Content-Type: multipart/mixed; boundary=\"".$uid. "\"\r\n\r\n";
    $header .= "This is a multi-part message in MIME format.\r\n";
    $header .= "--".$uid. "\r\n";
    $header .= "Content-type:text/html; charset=iso-8859-1\r\n";
    $header .= "Content-Transfer-Encoding: 7bit\r\n\r\n";
    $header .= $message. "\r\n\r\n";

    foreach ($files as $filename) 
    { 
        $file = $path.$filename; // path should be document root path. 
        $name = basename($file);
        $file_size = filesize($file);
        $handle = fopen($file, "r");
        $content = fread($handle, $file_size);
        fclose($handle);
        $content = chunk_split(base64_encode($content));

        $header .= "--".$uid. "\r\n";
        $header .= "Content-Type: application/octet-stream; name=\"".$filename. "\"\r\n"; // use different content types here
        $header .= "Content-Transfer-Encoding: base64\r\n";
        $header .= "Content-Disposition: attachment; filename=\"".$filename. "\"\r\n\r\n";
        $header .= $content. "\r\n\r\n";
    }
    $header .= "--".$uid."--"; 
    return mail($mailto, $subject, "", $header);
}

Hope it helps.