Untitled

<?php
    session_start();
	if (isset($_POST['submit']))
    {
        $username = $_POST['username'];
        $password = $_POST['password'];

        //Connect to db
        $conn = mysqli_connect('localhost', 'root','','studentsassistance','3306') or die ('Cannot connect to DB');
        $safeusername = mysqli_query($conn, "SELECT * FROM users WHERE username='$username'");
        $verifypassword = mysqli_query($conn, "SELECT password FROM users WHERE username='$safeusername'");

        if(mysqli_num_rows($safeusername) > 0)
        {
            if($password == mysqli_fetch_row($verifypassword))
            {
                $_SESSION['username'] = $username;
                echo "logged in";
            }

            else
            {
                $query = "Incorrect password.";
                echo "<script type='text/javascript'>alert('$query');</script>";
                header("Refresh:0; url=login.php");
            }
        }
        else
        {
            $query = "Username does not exist.";
            echo "<script type='text/javascript'>alert('$query');</script>";
            header("Refresh:0; url=login.php");
        }

        $result = mysqli_query($conn,$query);
        if(mysqli_query($conn, $query))
        {
            echo mysqli_affected_rows($conn);
        }
        else
        {
            echo "Error: ".mysqli_error($conn);

        }
    }
?>


<!DOCTYPE html>
<html>
<title>Home!</title>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://www.w3schools.com/w3css/4/w3.css">
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Lato">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<link rel="icon" href="images/favicon.ico">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<style>
body {font-family: "Lato", sans-serif}
.mySlides {display: none}
</style>
<body>

<!-- Navbar -->
<div class="w3-top">
  <div class="w3-bar w3-black w3-card">
    <a class="w3-bar-item w3-button w3-padding-large w3-hide-medium w3-hide-large w3-right" href="javascript:void(0)" onclick="myFunction()" title="Toggle Navigation Menu"><i class="fa fa-bars"></i></a>
    <a href="index.php" class="w3-bar-item w3-button w3-padding-large">Home</a>
    <a href="#" class="w3-bar-item w3-button w3-padding-large w3-hide-small">Submit</a>
    <a href="contact.php" class="w3-bar-item w3-button w3-padding-large w3-hide-small">Contact Us</a>
    <a href="#" class="w3-bar-item w3-button w3-padding-large w3-hide-small">Placeholder</a>
    <a href="signup.php" class="w3-bar-item w3-button w3-padding-large w3-hide-small">Sign Up</a>

    <a href="http://www.facebook.com"><i class="fa fa-facebook-official w3-hover-opacity w3-xlarge w3-padding-large"></i></a>
  </div>
</div>

<!-- Navbar on small screens -->
<div id="navDemo" class="w3-bar-block w3-black w3-hide w3-hide-large w3-hide-medium w3-top" style="margin-top:46px">
  <a href="index.html" class="w3-bar-item w3-button w3-padding-large">Home</a>
  <a href="#" class="w3-bar-item w3-button w3-padding-large">Submit</a>
  <a href="#contact" class="w3-bar-item w3-button w3-padding-large">Contact Us</a>
  <a href="#" class="w3-bar-item w3-button w3-padding-large">Placeholder</a>
  <a href="signup.php" class="w3-bar-item w3-button w3-padding-large w3-hide-small">Sign Up</a>
</div>

    <div class="w3-content" style="max-width:2000px;margin-top:46px"><h4 class="w3-wide">

        <?php
            echo "Welcome, $_SESSION[username]";
        ?>

      </h4>
    </div>

<!-- login Form-->
<div class="login-form" style="text-align: center; padding-top: 5%; padding-left: 30%; padding-right: 30%;">
    <form action="login.php" method="post">
		<h2>Login</h2>
		<p>Please fill in this form to login to your account!</p>
		<hr>
        <div class="form-group">
			<div class="input-group">
				<span class="input-group-addon"><i class="fa fa-user"></i></span>
				<input type="text" class="form-control" name="username" placeholder="Username" required="required">
			</div>
        </div>
		<div class="form-group">
			<div class="input-group">
				<span class="input-group-addon"><i class="fa fa-lock"></i></span>
				<input type="text" class="form-control" name="password" placeholder="Password" required="required">
			</div>
        </div>
		<div class="form-group">
            <button type="submit" name="submit" class="btn btn-primary btn-lg">Login</button>
        </div>
    </form>
</div>


<script>
</script>

</body>
</html>