HTML content email (PHP)

<?php

// Example 

$HTML         = "<b>This is a test</b>";
$from         = "test@test.com";
$to           = "this@that.com";
$subject     = "I'm sending a test HTML email";

sendHTMLemail($HTML,$from,$to,$subject);


function sendHTMLemail($HTML,$from,$to,$subject)
{
// First we have to build our email headers
// Set out "from" address

    $headers = "From: $from\r\n"; 

// Now we specify our MIME version

    $headers .= "MIME-Version: 1.0\r\n"; 

// Create a boundary so we know where to look for
// the start of the data

    $boundary = uniqid("HTMLEMAIL"); 
    
// First we be nice and send a non-html version of our email
    
    $headers .= "Content-Type: multipart/alternative;".
                "boundary = $boundary\r\n\r\n"; 

    $headers .= "This is a MIME encoded message.\r\n\r\n"; 

    $headers .= "--$boundary\r\n".
                "Content-Type: text/plain; charset=ISO-8859-1\r\n".
                "Content-Transfer-Encoding: base64\r\n\r\n"; 
                
    $headers .= chunk_split(base64_encode(strip_tags($HTML))); 

// Now we attach the HTML version

    $headers .= "--$boundary\r\n".
                "Content-Type: text/html; charset=ISO-8859-1\r\n".
                "Content-Transfer-Encoding: base64\r\n\r\n"; 
                
    $headers .= chunk_split(base64_encode($HTML)); 

// And then send the email ....

    mail($to,$subject,"",$headers);
    
}

?>