How to validate Joomla Login

joomlaLoginValidator.php

<?php
function validateLogin($username,$password){
			  jimport( 'joomla.user.authentication');
			  $auth = & JAuthentication::getInstance();
			  $credentials = array( 'username' => $username, 'password' => $password );
			  $options = array();
			  $response = $auth->authenticate($credentials, $options);
			  if ($response->status === JAUTHENTICATE_STATUS_SUCCESS) {
				$response->status = true;
				$user=JFactory::getUser($username);
				return $user;
			  } else {
				return false;
			  }
	}

$username=JRequest::getVar('username');
$password=JRequest::getVar('password');

if(validateLogin($username,$password)){

echo "User Login Sucessfully";
}
else{
echo "entered Wrong Username and Password";
}
?>