درخواست تکه کد زیر

[soonami]

قسمت رنگی تکه کد زیر رو میشه توضیح دهید که برای ارسال ایمیل هست؟؟؟

چه چیزی رو چک میکند ؟

تا خط SEND EMAIL

function spamcheck($field)
{
//filter_var() sanitizes the e-mail
//address using FILTER_SANITIZE_EMAIL
$field=filter_var($field, FILTER_SANITIZE_EMAIL);

//filter_var() validates the e-mail
//address using FILTER_VALIDATE_EMAIL
if(filter_var($field, FILTER_VALIDATE_EMAIL))
{
return TRUE;
}
else
{
return FALSE;
}
}

if (isset($_REQUEST['email']))
{//if "email" is filled out, proceed

//check if the email address is invalid
$mailcheck = spamcheck($_REQUEST['email']);
if ($mailcheck==FALSE)
{
echo "Invalid input";
}
_____________________



else
{//send email
$email = $_REQUEST['email'] ;
$subject = $_REQUEST['subject'] ;
$message = $_REQUEST['message'] ;
mail("someone@example.com", "Subject: $subject",
$message, "From: $email" );
echo "Thank you for using our mail form";
}
}
else
{//if "email" is not filled out, display the form
echo "<form method='post' action='mailform.php'>
Email: <input name='email' type='text' /><br />
Subject: <input name='subject' type='text' /><br />
Message:<br />
<textarea name='message' rows='15' cols='40'>
</textarea><br />
<input type='submit' />
</form>";
}
?>

</body>
</html>