Untitled

<?php
 require("connect.php");

$submit = $_POST['submit'];
$username = strtolower(strip_tags($_POST['username']));
$email = strip_tags($_POST['email']);
$password = strip_tags($_POST['password']);
$password_again = strip_tags($_POST['password_again']);
$date = date("Y-m-d ");

if($submit){
  if($username && $email && $password && $password_again){
    if($password == $password_again){
        $password = md5($password);

        $chk_username = mysql_query("SELECT username FROM users WHERE username = '$username'") or die("Error: ".mysql_error());
        $num_rows = mysql_num_rows($chk_username);

        if($num_rows == 0){
        $set_reg = mysql_query("INSERT INTO users (username, password, email, date) VALUES('$username','$password','$email','$date')") or die("Error: ". mysql_error());
        echo "Thank you for registering.";
        }else{
        echo "Sorry, the username <b>$username</b> is already taken.";
        }
    }else{
        echo "Your passwords do not match";
    }
  }else{
    echo "Please fill in <b>ALL</b> fields.";
  }
}
?>

<html>

<form action='register.php' method = 'POST' >
  <table>
  <tr>
    <td>Username:</td>
    <td><input type='text' name='username' /></td>
  </tr>
  <tr>
    <td>E-Mail:</td>
    <td><input type='text' name='email' /></td>
  </tr>
  <tr>
   <td>Password:</td>
   <td><input type='password' name='password' /></td>
   </tr>
   <tr>
   <td>Password again:</td>
   <td><input type='password' name='password_again' /></td>

  </tr>
  </table><p>
  <input  type='submit' name='submit' value='Register' />

</form>

</html>