<html>
  <head>
    <script>
var lastVal = 5;
var result = -1;

function fib(n) {
  if (n < 2) {
    return 1;
  } else {
    return fib(n-1) + fib(n-2);
  }
}

function calculate(e) {
  result = fib(lastVal++);
}

    </script>
  </head>
  <body>
  </body>
</html>