How Do I define properties for a class in php?

This block:

var $username="my_username";var $servername="localhost";var $database="my_DB";var $password="An_Awesome_Password";var $con;

Should come before the function(), not inside it; but still inside the class definition.

And it's good form to add an explicit visibility; private to start with:

class database  {    private $username="my_username";    private $servername="localhost";    // etc. etc.

Then, the functions refer to them as:

$this->username;$this->con;etc.

Ideally you will want to have those credentials to be passed in by the constructor:

private $servername;private $database;private $username;private $password;private $con;function __construct($host, $user, $password, $dbname){    $this->servername = $host;    $this->username = $user;    $this->password = $password;    $this->database = $dbname;}

Even more ideally, learn about PDO

Code styling aside, you need to define your variables outside the class methods but still inside the class. Something like:

class database {    var $username = "my_username";    // etc.    function connect() {        // connect code        // $this->username == "my_username"    }}

To access object property you need to use $this->property_name

 $this->con = mysql_connect($this->servername,$this->username,$this->password);

Class code would go like this:

<?phpclass database  {    var $username="my_username";    var $servername="localhost";    var $database="my_DB";    var $password="An_Awesome_Password";    var $con;    function connect()  {        $this->con = mysql_connect($this->servername,$this->username,$this->password);        if (!$this->con)  {            die('Could not connect: ' . mysql_error());        }    }    function disconnect()   {        $this->con = mysql_connect($this->servername,$this->username,$this->password);        if (!$this->con)  {            die('Could not connect: ' . mysql_error());        }        mysql_close($this->con);    }}?>