必须在 php.ini 文件中正确配置PHP ，并详细说明系统如何发送电子邮件。打开 / etc / 目录中的php.ini文件，并找到标题为 [邮件功能] 的部分。
Windows用户应确保提供了两个指令。第一个称为SMTP，它定义您的电子邮件服务器地址。第二个称为sendmail_from，它定义您自己的电子邮件地址。
Windows的配置应如下所示：
[mail function]
; For Win32 only.
SMTP = smtp.secureserver.net
; For win32 only
sendmail_from = webmaster@tutorialspoint.com
Linux用户只需要让PHP知道他们 sendmail 应用程序的位置即可。路径和任何所需的开关应指定给sendmail_path指令。
Linux的配置应该看起来像这样-
[mail function]
; For Win32 only.
SMTP =
; For win32 only
sendmail_from =
; For Unix only
sendmail_path = /usr/sbin/sendmail -t -i
现在您可以开始了-
发送纯文本电子邮件
PHP利用 mail（） 函数发送电子邮件。此功能需要三个必填参数，用于指定收件人的电子邮件地址，邮件主题和实际邮件，此外还有其他两个可选参数。
mail( to, subject , message , headers, parameters ); 这是每个参数的说明。
一旦调用了邮件功能，PHP将尝试发送电子邮件，如果成功，它将返回true；如果失败，则将返回false。
可以将多个收件人指定为逗号分隔列表中mail（）函数的第一个参数。
发送 html 电子邮件
当您使用PHP发送文本消息时，所有内容将被视为简单文本。即使您将HTML标签包含在文本消息中，它也将显示为简单文本，并且不会根据HTML语法设置HTML标签的格式。但是PHP提供了将HTML消息作为实际HTML消息发送的选项。
发送电子邮件时，您可以指定Mime版本，内容类型和字符集来发送HTML电子邮件。
例
以下示例将HTML电子邮件发送到xyz@somedomain.com，并将其复制到afgh@somedomain.com。您可以使用以下方式对程序进行编码：它应接收用户的所有内容，然后发送电子邮件。
<html>
<head>
<title>Sending HTML email using PHP</title>
</head>
<body>
<?php
$to = "xyz@somedomain.com";
$subject = "This is subject";
$message = "<b>This is HTML message.</b>";
$message .= "<h1>This is headline.</h1>";
$ header = "From:abc@somedomain.com \r\n";
$header .= "Cc:afgh@somedomain.com \r\n";
$header .= "MIME-Version: 1.0\r\n";
$header .= "Content-type: text/html\r\n";
$retval = mail ($to,$subject,$message,$header);
if( $retval == true ) {
echo "Message sent successfully...";
}else {
echo "Message could not be sent...";
}
?>
</body>
</html> 通过电子邮件发送附件
要发送包含混合内容的电子邮件，需要将 Content-type 标头设置为 multipart / mixed 。然后可以在 边界 内指定文本和附件节。
边界以两个连字符开头，后跟一个唯一的数字，该数字不能出现在电子邮件的消息部分。PHP函数 md5（） 用于创建32位十六进制数字以创建唯一数字。表示电子邮件最后部分的最后边界也必须以两个连字符结尾。
<?php
// request variables // important
$from = $_REQUEST["from"];
$emaila = $_REQUEST["emaila"];
$filea = $_REQUEST["filea"];
if ($ file a) {
function mail_attachment ($from , $to, $subject, $message, $attachment){
$fileatt = $attachment; // Path to the file
$fileatt_type = "application/octet-stream"; // File Type
$start = strrpos($attachment, '/') == -1 ?
strrpos($attachment, '//') : strrpos($attachment, '/')+1;
$fileatt_name = substr($attachment, $start,
strlen($attachment)); // Filename that will be used for the
file as the attachment
$email_from = $from; // Who the email is from
$subject = "New Attachment Message";
$email_subject = $subject; // The Subject of the email
$email_txt = $message; // Message that the email has in it
$email_to = $to; // Who the email is to
$headers = "From: ".$email_from;
$file = fopen($fileatt,'rb');
$data = fread($file,filesize($fileatt));
fclose($file);
$msg_txt="\n\n You have recieved a new attachment message from $from";
$semi_rand = md5(time());
$mime_boundary = "==Multipart_Boundary_x{$semi_rand}x";
$headers .= "\nMIME-Version: 1.0\n" . "Content-Type: multipart/mixed;\n" . "
boundary=\"{$mime_boundary}\"";
$email_txt .= $msg_txt;
$email_message .= "This is a multi-part message in MIME format.\n\n" .
"--{$mime_boundary}\n" . "Content-Type:text/html;
charset = \"iso-8859-1\"\n" . "Content-Transfer-Encoding: 7bit\n\n" .
$email_txt . "\n\n";
$data = chunk_split(base64_encode($data));
$email_message .= "--{$mime_boundary}\n" . "Content-Type: {$fileatt_type};\n" .
" name = \"{$fileatt_name}\"\n" . //"Content-Disposition: attachment;\n" .
//" filename = \"{$fileatt_name}\"\n" . "Content-Transfer-Encoding:
base64\n\n" . $data . "\n\n" . "--{$mime_boundary}--\n";
$ok = mail($email_to, $email_subject, $email_message, $headers);
if($ok) {
echo "File Sent Successfully.";
unlink($attachment); // delete a file after attachment sent.
}else {
die("Sorry but the email could not be sent. Please go back and try again!");
}
}
move_uploaded_file($_FILES["filea"]["tmp_name"],
' temp /'.basename($_FILES['filea']['name']));
mail_attachment("$from", "youremailaddress@gmail.com",
"subject", "message", ("temp/".$_FILES["filea"]["name"]));
}
?>
<html>
<head>
<script language = "javascript" type = "text/javascript">
function CheckData45() {
with(document.filepost) {
if(filea.value ! = "") {
document.getElementById('one').innerText =
"Attaching File ... Please Wait";
}
}
}
</script>
</head>
<body>
<table width = "100%" height = "100%" border = "0"
cellpadding = "0" cellspacing = "0">
<tr>
< td align = "center">
<form name = "filepost" method = "post"
action = "file.php" enctype = "multipart/form-data" id = "file">
<table width = "300" border = "0" cellspacing = "0"
cellpadding = "0">
<tr valign = "bottom">
<td height = "20">Your Name:</td>
</tr>
<tr>
<td><input name = "from" type = "text"
id = "from" size = "30"></td>
</tr>
<tr valign = "bottom">
<td height = "20">Your Email Address:</td>
</tr>
<tr>
<td class = "frmtxt2"><input name = "emaila"
type = "text" id = "emaila" size = "30"></td>
</tr>
<tr>
<td height = "20" valign = "bottom">Attach File:</td>
</tr>
<tr valign = "bottom">
<td valign = "bottom"><input name = "filea"
type = "file" id = "filea" size = "16"></td>
</tr>
<tr>
<td height = "40" valign = "middle"><input
name = "Reset2" type = "reset" id = "Reset2" value = "Reset">
<input name = "Submit2" type = "submit"
value = "Submit" onClick = "return CheckData45()"></td>
</tr>
</table>
</form>
<center>
<table width = "400">
<tr>
<td id = "one">
</td>
</tr>
</table>
</center>
</td>
</tr>
</table>
</body>
</html> 
