PHP first Class db connect

registration.php

<html>
<head>
    <title>Registration</title>
</head>
<body>
        <h2>Register</h2>
    <form method="post" action="regProcess.php">
            <label>Username</label>
            <input type="text" name="username">
            <label>Email</label>
            <input type="email" name="email">
            <label>Password</label>
            <input type="password" name="password">
            <button type="submit" class="btn" name="register_btn">Register</button>
    </form>
</body>
</html>


dbconn.php

<?php
$con = mysqli_connect("localhost","root","","crud");
if (mysqli_connect_errno())
  {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
  }
else
  {
    //echo "Database Connection Successfull";
  }
?>


regProcess.php

<html>
<head>
    <title>Login</title>
</head>
<body>
        <h2>Register</h2>
    <form method="post" action="regProcess.php">
            <label>Username</label>
            <input type="text" name="username">
            <label>Password</label>
            <input type="password" name="password">
            <button type="submit" class="btn" name="login_btn">Login</button>
    </form>
</body>
</html>


login.php

<html>
<head>
    <title>Login</title>
</head>
<body>
        <h2>Register</h2>
    <form method="post" action="loginProcess.php">
            <label>Username</label>
            <input type="text" name="username">
            <label>Password</label>
            <input type="password" name="password">
            <button type="submit" class="btn" name="login_btn">Login</button>
    </form>
</body>
</html>


loginProcess.php

<?php
        require('dbconn.php');
        if (isset($_POST['login_btn'])){
        $username    = $_POST['username'];
        $password = $_POST['password'];

        $query = "SELECT * FROM user WHERE username='$username' AND password='$password'";
        $results = mysqli_query($con, $query);

        if (mysqli_num_rows($results) == 1) {
        echo "$username Login Successfully";
        }
        else
        {
            echo "Login faild";
        }
    }
?>