Private Members in JavaScript

Private Members in JavaScript

<script type="text/javascript" charset="utf-8">
function doc(argument) {
 document.write("<p>\n");
 document.write(argument);
 document.write("</p>\n");
}

function Container(param) {

 function dec() {
  // private function
  if (secret > 0) {
   // encloures 
   secret -= 1;
   return true;
  } else {
   return false;
  }
 }

 this.member = param;
 var secret = 3; // private variables only be made in constructor function
 var that = this;

 this.service = function () {
  // privileged function
  if (dec()) {
   //return that.member;
   return this.member;
  } else {
   return null;
  }
 };
}

var myContainer = new Container('abc');
doc(myContainer.service()); // abc
doc(myContainer.service()); // abc
doc(myContainer.service()); // abc
doc(myContainer.service()); // null
</script>