问使用PHP的mysql_connect功能的正确方式？

EN

$.ajax(
{
    url: "public/includes/userCreate.php",
    type: "POST",     
    data: 
    { 
        username: user_username, 
        forename: user_forename,
        surname: user_surname,
        email: user_email01,
        password: user_password01
    }, 
    success: function(html) 
    {             
        $('#web_Content').html(html);
    }      
});

<?php
    $new_Username = $_POST['username'];
    $new_Forename = $_POST['forename'];
    $new_Surname = $_POST['surname'];
    $new_Email = $_POST['email'];
    $new_Password = $_POST['password'];

    echo "Username is: " . $new_Username;
    echo "Forename is: " . $new_Forename;
    echo "Surname is: " . $new_Surname;
    echo "Email is: " . $new_Email;
    echo "Password is: " . $new_Password;   
?>

mysql_connect("localhost","root","mypass");
mysql_select_db("mydatabase");
mysql_query("INSERT INTO users (user_Username, user_Email, user_Password) VALUES ('TestMan', 'tom@mail.com', 'qwerty' ) ");