PHP - Php To Create New .js File For Each Registered User

<?php

	// Start the session in case of errors to display within the page of user creation
	session_start();
	$err_msg = array();
	$errflag = false;



	// Check if the submit button was pressed
	if ($_SERVER['REQUEST_METHOD'] === 'POST'
		&& $_POST['submit'] === 'Skapa')
	{
		// Crypt password
		$options = ['cost' => 10];

		$username = strip_tags($_POST['uname']);
		$password = strip_tags(password_hash($_POST['pword'], PASSWORD_DEFAULT, $options));
		$email = strip_tags($_POST['uname'], '@');

		// Check so all the fields are filled
		if ($_POST['uname'] == '' || $_POST['pword'] == '' || $_POST['pwordcheck'] == '')
		{
			$err_msg[] = 'Please enter all fields<br>';
			$errflag = true;
		}

		// See if passwords and confirm matches
		if ($_POST['pword'] !== $_POST['pwordcheck'])
		{
			$err_msg[] = 'Passwords doesn\'t match!<br>';
			$errflag = true;
		}

		// Check password length, atleast 8 characters
		if (strlen($_POST['pword']) < 7)
		{
			$err_msg[] = 'Password must be atleast 8 characters long';
			$errflag = true;
		}

		// Check if email exists
		include_once('../includes/db.inc.php');
		$db = new PDO(DB_INFO, DB_USER, DB_PASS);

		$sql = "SELECT COUNT(*) AS count FROM movies WHERE email = :emailadress";
			$stmt = $db->prepare($sql);
			$stmt->bindParam(':emailadress', $email);
			$stmt->execute();
			$row = $stmt->fetch(PDO::FETCH_ASSOC);

		if ($row > 0)
		{
			$err_msg[] = 'Email already taken!';
			$errflag = true;
			$db = NULL;
		}
		

		// Check if user exists
		include_once('../includes/db.inc.php');
		$db = new PDO(DB_INFO, DB_USER, DB_PASS);

		$sql = "SELECT uname FROM users WHERE uname = :username";
			$stmt = $db->prepare($sql);
			$stmt->bindParam(':username', $username);
			$stmt->execute();
			$row = $stmt->fetch(PDO::FETCH_ASSOC);

		if ($row > 0)
		{
			$err_msg[] = 'User already exists';
			$errflag = true;
			$db = NULL;
		}

		if ($errflag = false)
		{
			// Everything passed, create the user!
			include_once('../includes/db.inc.php');
			$db = new PDO(DB_INFO, DB_USER, DB_PASS);

			$sql = "INSERT INTO users (uname, pword, email) VALUES (:username, :password, :emailadress)";
				$stmt = $db->prepare($sql);
				$stmt->bindParam(':username', $username);
				$stmt->bindParam(':password', $password);
				$stmt->bindParam(':emailadress');
				$stmt->execute();

			$_SESSION['uname'] = $username;
			header('Location: ../template/header.php');
			exit;
		}
				
		// If any error, send the user back and display messages
		if ($errflag == true)
		{
			$_SESSION['err_msg'] = $err_msg;
			session_write_close();
			header('Location: ../user/create.php');
			exit;
		}
	}

	else
	{
		$_SESSION['err_msg'] = $err_msg;
			session_write_close();
			header('Location: ../user/create.php');
		exit;
	}

?>