server

<?php
   session_start();
   $username="";
   $email="";
   $errors=array();
   $db=mysqli_connect('localhost','root','','registration');
   if(isset($_POST['register'])){
   	   $username=$_POST['username'];
   	   $email=$_POST['email'];
   	   $password_1=$_POST['password_1'];
   	   $password_2=$_POST['password_2'];
   	   if(empty($username)){
            array_push($errors,"Username is required");
   	   }
   	   if(empty($email)){
            array_push($errors,"Email is required");
   	   }
   	   if(empty($password_1)){
            array_push($errors,"Password is required");
   	   }
   	   if($password_1!=$password_2){
   	   	  array_push($errors,"Passwords do not match");
   	   }
   	   if(count($errors)==0){
   	   	  $password=md5($password_1);
   	   	  //$sql="INSERT INTO users(username,email,password) VALUES('$username','$email','$password')";
   	   	  //mysqli_query($db,$sql);
   	   	  $__SESSION['username']=$username;
   	      $__SESSION['success']="You are logged in";
   	      //session_regenerate_id(true);
   	   	  header('location: index.php');
   	   }
   }
?>