I am learning php and MySQL to do a course project, but I got some problem here.
Here is my code in index.php (referenced from https://htmlcssphptutorial.wordpress.com/2015/07/07/simple-user-registration-login-script-in-php-and-mysql/):
<?php
session_start();
?>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Login</title>
<link rel="stylesheet" href="css/style.css" />
</head>
<body>
<?php
require('db.php');
// If form submitted, insert values into the database.
if (isset($_POST['username'])){
$username = $_POST['username'];
$password = $_POST['password'];
$username = stripslashes($username);
$username = mysql_real_escape_string($username);
$password = stripslashes($password);
$password = mysql_real_escape_string($password);
//Checking is user existing in the database or not
$query = "SELECT * FROM `users` WHERE username='$username' and password='".md5($password)."'";
$result = mysql_query($query) or die(mysql_error());
$rows = mysql_num_rows($result);
if($rows==1){
$_SESSION['username'] = $username;
header("Location: index.php"); // Redirect user to index.php
}else{
echo "<div class='form'><h3>Username/password is incorrect.</h3><br/>Click here to <a href='login.php'>Login</a></div>";
}
}else{
?>
<div class="form">
<h1>Log In</h1>
<form action="" method="post" name="login">
<input type="text" name="username" placeholder="Username" required />
<input type="password" name="password" placeholder="Password" required />
<input name="submit" type="submit" value="Login" />
</form>
<p>Not registered yet? <a href='registration.php'>Register Here</a></p>
</div>
<?php } ?>
</body>
</html>
And it gives me error message:
Warning: Cannot modify header information - headers already sent by (output started at /Library/WebServer/Documents/login.php:11) in /Library/WebServer/Documents/login.php on line 27
I googled it and it might be the html between two phps. however, if I put the html first and than a big chunk of php code, it gives me error
Warning: session_start(): Cannot send session cache limiter – headers already sent (output started at /website/login.php:15) in /website/login.php on line 17
Any idea how to get around with it? Thanks in advance!
