Untitled

<?php
	if (isset($_SESSION['id'])){
		header("Location: index.php");
	}
	if(isset($_POST['register'])) {
		include_once("db.php");
		$username = strip_tags($_POST['username']);
		$password = strip_tags($_POST['password']);
		$password_confirm = strip_tags($_POST['password_confirm']);
		$email = strip_tags($_POST['email']);

		$username = stripslashes($username);
		$password = stripslashes($password);
		$password_confirm = stripslashes($password_confirm);
		$email = stripslashes($email);

		$username = mysqli_real_escape_string($db, $username);
		$password = mysqli_real_escape_string($db, $password);
		$password_confirm = mysqli_real_escape_string($db, $password_confirm);
		$email = mysqli_real_escape_string($db, $email);

		$password = md5($password);
		$password_confirm = md5($password_confirm);

		$sql_store = "INSERT into users (username, password, email) VALUES ('$username','$password','$email')";

		$sql_fetch_username = "SELECT username FROM users WHERE username = '$username'";
		$sql_fetch_email = "SELECT email FROM users WHERE email = '$email'";

		$query_username = mysqli_query($db, $sql_fetch_username);
		$query_email = mysqli_query($db, $sql_fetch_email);

		if(mysqli_num_rows($query_username)) {
		header("Refresh: 0; url=register.php");
		echo "<script>alert('Ya existe un usuario con ese nombre');</script>";
		return;
		}
		if ($username == "") {
			header("Refresh: 0; url=register.php");
			echo "<script>alert('Ingresa un usuario.');</script>";
			return;
		}
		if (empty($password)){
		header("Refresh: 0; url=register.php");
		echo "<script>alert('Ingresa una contraseña.');</script>";
		return;
		}

		if ($password != $password_confirm) {
			header("Refresh: 0; url=register.php");
			echo "<script>alert('Contraseñas no son similares.');</script>";
			return;
		}

		if(!filter_var($email, FILTER_VALIDATE_EMAIL) || $email == "") {
			header("Refresh: 0; url=register.php");
			echo "<script>alert('Este correo no es valido.');</script>";
			return;
		}

		if(mysqli_num_rows($query_email)) {
			header("Refresh: 0; url=register.php");
			echo "<script>alert('Este correo ya esta en uso.');</script>";
			return;
		}
		mysqli_query($db, $sql_store);
		header("Refresh: 0; url=login.php");
		echo "<script>alert('Registro completado, inicia sesión.');</script>";

	}
  ?>


<!DOCTYPE html>

<html>
<head>
<style type="text/css">
	.formulario {
		border-radius: 15px;
		height: 20px;
		text-indent: 10px;
		width: 40%;
		height: 30px;
		margin:5px;
	}
</style>

<link rel="stylesheet" type="text/css" href="css/main.css">
	<title>Registrarse</title>
</head>
<body>
<div class="post" style="text-align: center;">
	<form action="register.php" method="post" enctype="multipart/from-data">
		<input class="formulario" type="text" name="username" autofocus="" placeholder="Nombre de usuario"><br>
		<input class="formulario"  type="password" name="password" placeholder="Contraseña"><br>
		<input class="formulario"  type="password" name="password_confirm" placeholder="Confirma la contraseña"><br>
		<input class="formulario" type="text" name="email" placeholder="Correo electronico"><br>
		<input class="boton" style="width: auto; text-indent: 0px; padding: 20px;" type="submit" name="register" value="Registrarse">
	</form>

</div>
</body>
</html>