19.2. How to allow HTML in the Newsletter

Figure 19-3. Administration panel: Newsletter.

Administration panel: Newsletter.

If you want to use HTML, instead of only plain text in the Newsletter from the administration panel, you have to do the following:

Replace the function newsletter_send() in admin/modules/newsletter.php with:

function newsletter_send($title, $content) {
    global $user_prefix, $sitename, $dbi, $nukeurl, $adminmail;
    $send_html_messages = "yes";
    $from = $adminmail;
    $subject = "[$sitename Newsletter]: ".stripslashes($title)."";
    $content = stripslashes($content);
    $content = "$sitename "._NEWSLETTER."\n\n\n$content\n\n- 
$sitename "._STAFF."\n\n\n\n\n\n"._NLUNSUBSCRIBE."";
    $result = sql_query("select email from ".$user_prefix.
"_users where newsletter='1'", $dbi);
    while(list($email) = sql_fetch_row($result, $dbi)) {
        $xheaders = "From: " . $sitename . " <" . $adminmail . ">\n";
        $xheaders .= "X-Sender: <" . $adminmail . ">\n";
        $xheaders .= "X-Mailer: PHP\n"; // mailer
        $xheaders .= "X-Priority: 6\n"; // Urgent message!
        if ($send_html_messages == "yes") {
            $xheaders .= "Content-Type: text/html; 
charset=iso-8859-1\n"; // Mime type
        }
        mail("$email","$subject","$content",$xheaders);
    }
    Header("Location: admin.php?op=newsletter_sent");
}

and the function massmail_send() with

function massmail_send($title, $content) {    
    global $user_prefix, $sitename, $dbi, $nukeurl, $adminmail;
    $send_html_messages = "yes";
    $from = $adminmail;
    $subject = "[$sitename]: $title";
    $content = stripslashes($content);
    $content = ""._FROM.": $sitename\n\n\n\n$content\n\n\n\n- 
    $sitename "._STAFF."\n\n\n\n"._MASSEMAILMSG."";
    $result = sql_query("select email from ".$user_prefix
    ."_users where uid != '1'", $dbi);
    while(list($email) = sql_fetch_row($result, $dbi)) {
        $xheaders = "From: " . $sitename . " <" . $adminmail . ">\n";
        $xheaders .= "X-Sender: <" . $adminmail . ">\n";
        $xheaders .= "X-Mailer: PHP\n"; // mailer
        $xheaders .= "X-Priority: 6\n"; // Urgent message!
        if ($send_html_messages == "yes") {
            $xheaders .= "Content-Type: text/html;
            charset=iso-8859-1\n"; // Mime type
        }
        mail("$email","$subject","$content",$xheaders);
    }
    Header("Location: admin.php?op=massmail_sent");
}

The changes are in both functions the same: a flag, $send_html_messages, is checked and if set to "yes", the headers of the Newsletter mails (stored in the $xheaders variable) get an extra line for the MIME type:

Content-Type: text/html; charset=iso-8859-1

See also HTML Newsletter, but be warned that the code presented in that link, may not escape double quotes, probabbly due to an upgrade bug in the forums.