javascript Ö® Closure

http://javascript.crockford.com/private.html
function a() {
var i = 0;
function b() {
alert(++i);
}
return b;
}
var c = a();
c();
 
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function Container(param) {
this.member = param;
}
var myContainer = new Container('abc'); //member='abc'
Container.prototype.stamp = function (string) {
return this.member + string;
}
myContainer.stamp('def') //member='abcdef'
function Container(param) {
//private method
function dec() {
if (secret > 0) {
secret -= 1;
return true;
} else {
return false;
}
}
this.member = param;
var secret = 3;
var that = this;
//privileged method
this.service = function () {
if (dec()) {
return that.member;
} else {
return null;
}
};
}
myContainer.service() //abc(first) null(second.....)