JS Singleton Class

JavaScript

var SingletonClass = (function() {
            function SingletonClass() {
                //do stuff
            }
            var instance;
            var n;
            return {
                getInstance: function() {
                    if (instance == null) {
                        instance = new SingletonClass();
                        // Hide the constructor so the returned objected can't be new'd...
                        instance.constructor = null;
                        n = 0;
                    }
                    else n++;
                   alert("Value" + n);
                    return instance;
                }
            };
        })();
var test = SingletonClass.getInstance();