Sending email with attachment in core PHP

email_attachment.php

<?php
try {

	$fileatt = "";
	$fileatt_name = $fileatt. "file.pdf";

	$email_from = "support@mathkings.com";
	$email_subject = "attachment test-subject";
	$email_txt = "attachment test-body";
	$email_to = "janasir35@gmail.com";

	$headers = "From: ".$email_from;

	$file = fopen($fileatt_name,'rb');
	$data = fread($file,filesize($fileatt_name));
	fclose($file);

	$data = chunk_split(base64_encode($data));

	$fileatt_name = substr($fileatt_name, strlen($fileatt));

	$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}\"";

	$email_message = "This is a multi-part message in MIME format.\n\n" .
	"--{$mime_boundary}\n" .
	"Content-Type:text/html; charset=\"iso-8859-1\"\n" .
	"Content-Transfer-Encoding: 7bit\n\n". $email_txt . "\n\n";

	$email_message .= "--{$mime_boundary}\n" .
	"Content-Type: application/pdf;\n" .
	" name=\"{$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 "<p>mail sent!</p>";
	} else {
	    echo "<p>mail could not be sent!</p>";
	}

} catch (\Exception $e) {

    echo $e->getMessage();

}