通用发送电子邮件 html 或纯文本 php

几天来，我一直在总结这样一个事实：我可以创建一个发送 HTML 邮件模板的脚本，如果用户的客户端无法读取 HTML，纯文本列表可能无法接收 HTML 电子邮件。

请一些关于如何做到这一点的通用建议。我查遍了整个互联网，但我真的不知道。

非常感谢您的建议。

您应该添加名为的电子邮件的 html 和纯文本版本multipart/alternative在同一电子邮件正文中：

<?php

        $from = "a asd"; 
        $email = "[email protected] /cdn-cgi/l/email-protection";
        $email = "[email protected] /cdn-cgi/l/email-protection";

                $semi_rand = md5(time());
                $mime_boundary = "==MULTIPART_BOUNDARY_$semi_rand";
                $mime_boundary_header = chr(34) . $mime_boundary . chr(34);
                $boundary = "nextPart";
                $headers = "From: \"".$from."\" <".$email.">\n";

                $headers .=  "To: ". $new_to ."\n";

                $headers .= "Reply-To: \"". $from. "\" <" . $email . ">\r\n";
                $headers .= "Return-Path: <". $email .">\r\n";
                $headers .= "MIME-Version: 1.0\r\n";
                $headers .= "Content-Type: multipart/alternative;\n boundary=" . $mime_boundary_header ;
                $headers .= "\n--$boundary\n"; // beginning \n added to separate previous content
                $headers .= "Content-type: text/plain; charset=iso-8859-1\r\n";
                $headers .= "\n--$boundary\n";
                $headers .= "Content-type: text/html; charset=iso-8859-1\r\n";
                $headers .= "Content-Transfer-Encoding:base64\r\n";
$body = "

--$mime_boundary
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

". strip_tags($messageBody) ."

--$mime_boundary
Content-Type: text/html; charset=us-ascii
Content-Transfer-Encoding:base64

". chunk_split(base64_encode($messageBody)) ."

--$mime_boundary--";

mail(null,$sub,$body,$headers,"-f".$email);