I have been building a website which includes a login page. I need to redirect the user to their profile page once they've logged in successfully, but I don't know how to do that in PHP as this is my first website. I've searched the internet and have been told that the header() function should do the trick, but it will only work if I haven't output any information before using it.
The problem is that I've outputted a bunch of information Including the HTML to build the login page itself. So how do I redirect the user from one page to the next?
What options do I have? Also, what is the best practice in these instances?
EDIT: Here's my entire login.php page:
echo "<!DOCTYPE html>
<link rel='stylesheet' href='stylesheet.css' type='text/css'>
<form action='login.php' method='post'>
Name<br /> <input type='text' name='username' class='form'/><br />
<input type='password' name='password' class='form'/> <input type='submit' value='Login' class='button' />
if ($_SERVER['REQUEST_METHOD'] == 'POST')
$username = $_POST["username"];
$password = $_POST["password"];
$dbhost = "localhost";
$dbuser = "root";
$dbpass = "root";
$conn = mysql_connect($dbhost, $dbuser, $dbpass) or die ("Error connecting to database");
$dbname = "database";
$query = "SELECT username FROM users WHERE username = '$username' AND password = '$password'";
$result = mysql_query($query) or die ("Failed Query of " . $query);
while($row = mysql_fetch_assoc($result))
$_SESSION["user"] = $username;