Edit in JSFiddle

//The functions we are going to use 
function A() {}
function B() {}
function C() {}
function D() {}
function E() {}

//set up the inheritance chain 
D.prototype = new E();
C.prototype = new D();
B.prototype = new C();
A.prototype = new B();

//Add custom functions to each
A.prototype.foo = function() {
    console.log("a");
};
B.prototype.bar = function() {
    console.log("b");
};
C.prototype.baz = function() {
    console.log("c");
};
D.prototype.wee = function() {
    console.log("d");
};
E.prototype.woo = function() {
    console.log("e");
};

//Some tests
a = new A();
a.foo();
a.bar();
a.baz();
a.wee();
a.woo();