Untitled

<?php
require("connect.php");
require("functions.php");

if(!empty($_POST)){
    $submit = $_POST['submit'];
    $username = mysql_real_escape_string($_POST['username']);
    $email = mysql_real_escape_string($_POST['email']);
    $password = mysql_real_escape_string($_POST['password']);
    $password_again = mysql_real_escape_string($_POST['password_again']);
    $date_set = date_default_timezone_set('America/New_York');
    $date = date("Y-m-d ");

    if($submit){
      if($username && $email && $password && $password_again){

        if($password == $password_again){

          $complex = preg_match('/\d/',$password);
          $pass_len = strlen($password);
          if($complex && $pass_len >= 8){

            $salt = salt_gen(20);
            $password = sha1($password.$salt);

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

            if($num_rows === 0){
              $set_reg = mysql_query("INSERT INTO users (username, password, email, salt, date) VALUES('$username','$password','$email','$salt','$date')") or die("Error, inserting user");
              echo "Thank you for registering.";
            }else{
              die("Sorry, the username <b>$username</b> is already taken.");
            }
          }else{
            die ("For security, you password my be at least</br> 8 characters long and contain numbers!");
          }


        }else{
          die("Your passwords do not match");
        }
      }else{
        die("Please fill in <b>ALL</b> fields.");
      }
    }
}
?>

<!DOCTYPE HTML>
<html>

<head>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" >
<title>Register</title>
</head>

<body>
<form action='register.php' method = 'POST' >
  <table>
  <tr>
    <td>Username:</td>
    <td><input type='text' name='username' value='<?php if(!empty($_POST))echo $username;?>' /></td>
  </tr>
  <tr>
    <td>E-Mail:</td>
    <td><input type='text' name='email' value='<?php if(!empty($_POST))echo $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>
   <tr>

   <td><input  type='submit' name='submit' value='Register' /></td>

  </tr>
  </table><p>


</form>
</body>
</html>