I'm very new to web programming, but I have some data that I would really like to present in a constantly updated time series graph on my website. So I have been trying to prototype some code that will display the latest integer value that has been added to a database. The database table I want to reference is being constantly inserted with integer values. My question is this; I'm trying to use a combination of JavaScript and php to display the latest entry into the database when a button on the website is pressed. However the only integer I can get back is the last integer that was present in the database when the page originally loaded. It appears the php function I am using to grab data from the database is run as soon as the page is loaded and does not update after each button press. Is this a limitation of php (or my knowledge of php). Any help would be much appreciated.

(Php fonksiyonu)

function getData()

{ include "config.php";

  $db = mysql_connect($dbhost,$uname,$pass);
  mysql_select_db ($dbname) or die ("Cannot connect");

  $query = "SELECT numCalls FROM $tname ORDER by claatime DESC LIMIT 1";
  $result = mysql_query($query);

  while($r=mysql_fetch_array($result))
  {
     $numCalls = $r["numCalls"];
  }
  return $numCalls;

}

(Javascript fonksiyonu)

  function getNum()
  {
     var x = <?php echo getData()?>;
     alert('the latest number is ' +x);
  }