How to implement mail() function in PHP?

As you don't have a smtp server on your localhost, I suggest to use the gmail smtp for start. PHPMailer[^] is a great library that you can use and here you can find an example about how to use it with gmail: https://github.com/PHPMailer/PHPMailer/blob/master/examples/gmail.phps[^].

If you use the PHPMailer, then you should change your mail.php to something like:

<?php

  //Email information
  $admin_email = "jsathish1989@gmail.com";
  $email = $_REQUEST['email'];
  $subject = $_REQUEST['subject'];
  $comment = $_REQUEST['comment'];

//SMTP needs accurate times, and the PHP time zone MUST be set
//This should be done in your php.ini, but this is how to do it if you don't have access to that
date_default_timezone_set('Etc/UTC');

require 'path_to_mailer/PHPMailerAutoload.php';

$mail = new PHPMailer(); // create a new object
$mail->IsSMTP(); // enable SMTP
$mail->SMTPDebug = 1; // debugging: 1 = errors and messages, 2 = messages only
$mail->SMTPAuth = true; // authentication enabled
$mail->SMTPSecure = 'ssl'; // secure transfer enabled REQUIRED for GMail
$mail->Host = "smtp.gmail.com";
$mail->Port = 465; // or 587
$mail->IsHTML(true);
$mail->Username = "YOUR_GMAIL_USER@gmail.com";
$mail->Password = "YOUR_GMAIL_PASSW";
$mail->SetFrom($email);
$mail->Subject = $subject;
$mail->Body = $comment;
$mail->AddAddress($admin_email);
 if(!$mail->Send())
 {
    echo "Mailer Error: " . $mail->ErrorInfo;
 }
    else
 {
    echo "Message has been sent";
 }
?>