1) the label: {div {@ id="label"} There have been no clicks yet }
2) the button: {input {@ type="button" value="click me" onclick="CLICKAPP.inc()" }}
3) the script: {script °° code °°} where code is a single function:

var CLICKAPP = (function() {
  var counter = 0;
  var inc = function() {
      counter++;
      getId('label').innerHTML =
      'There are ' + counter + ' clicks now';
  };
  return {inc:inc}
})();