我需要生成包含变音符号的德语电子邮件。在电子邮件本身中,这非常有效,但在电子邮件的主题中却不行。我尝试了许多不同的变音字母,它们似乎都可以工作,除了 ü。我还尝试了不同的邮件库(HTMLMimeMail 和 PHPMailer),但它们都失败了:
$mail = new htmlMimeMail();
$mail->setTextEncoding("base64");
$mail->setHTMLEncoding("base64");
$mail->setTextCharset("UTF-8");
$mail->setHTMLCharset("UTF-8");
$mail->setHeadCharset("UTF-8");
$mail->setSMTPParams(mailinglist_smtp_host,mailinglist_smtp_port);
$mail->setHtml("test");
$mail->setFrom("test@test.nl");
$mail->setSubject("The ï, ö, ë, ä, and é work, but when adding the ü it doesn't");
$recipients[] = "me@myhost.nl";
$mail->send($recipients);
&
$mail = new PHPMailer();
$mail->IsMail();
$mail->FromName = 'test';
$mail->From = 'test@test.nl';
$mail->AddAddress("me@myhost.nl");
$mail->Subject = "The ï, ö, ë, ä, and é work, but when adding the ü it doesn't";
$mail->Body = "test";
$mail->Send();
谁能帮我找到这个问题的根源和解决方案?