SQL INSERT TROUBLE

I'm sitting infront of this code for 2 hours i cant figure out whats wrong :(

I've been trying to have a html form which calls the php function to insert the information from the form into the database but for some reason does not work :/

here is my form code :

<?php include 'connection.php'; ?>
<html>
<body>
<form action="user_create.php" method="POST">
username: <input type="text" name="username"/>
password: <input type="text" name="password"/>
email: <input type="text" name="email"/>
<input type="submit" name='submit' value="user_create"/>
</form>
</body>
</html>

database connection

<?php 

//Connecting databases 

$localhost  = ""; 
$dbuser = "";
$dbpass = "m"; 
$dbname = ""; 

$connect = mysql_connect($localhost, $dbuser, $dbpass);
mysql_select_db("$dbname", $connect);  

?>

my php function

<?php include 'connection.php';?>
<?php
if (isset($_POST['submit']))
    {
    $username = $_POST['username']; 
    $password = $_POST['password']; 
    $email = $_POST['email']; 


$query = mysql_query("INSERT INTO users( username,password,email,type) 
VALUES ('$username', '$password', '$email','1')");
mysql_query($query); 
echo '<script type="text/javascript">alert("You have been registered");</script>';
}
else
    {
        echo '<script type="text/javascript">alert("jo");</script>';
    }

?>

Are you connecting properly?

$dbuser = "";

Maybe must be "root" or other user?

Check this part :

//Connecting databases 

$localhost  = ""; 
$dbuser = "";
$dbpass = "m"; 
$dbname = "";

You should use PHP-PDO in order to avoid from SQL Injection attacks also it will fix insert trouble too.

<?php
/*** mysql hostname ***/
$hostname = 'localhost';

/*** mysql username ***/
$username = 'username';

/*** mysql password ***/
$password = 'password';

try {
    $dbh = new PDO("mysql:host=$hostname;dbname=animals", $username, $password);
    /*** echo a message saying we have connected ***/
    echo 'Connected to database<br />';

    /*** INSERT data ***/
    $sql = "INSERT INTO users(username,
            password,
            email,
            type) VALUES (
            :username, 
            :password, 
            :email, 
            :type)";

    $stmt = $pdo->prepare($sql);

    $stmt->bindParam(':username', $_POST['username'], PDO::PARAM_STR);      
    $stmt->bindParam(':password', $_POST['password'], PDO::PARAM_STR);
    $stmt->bindParam(':email', $_POST['email'], PDO::PARAM_STR);
    $stmt->bindParam(':type', $_POST['type'], PDO::PARAM_INT);

$stmt->execute(); 
    }
catch(PDOException $e)
    {
    echo $e->getMessage();
    }
?>