count = 0;
function Klacc(){
}
Klacc.extend = function(Child, Parent)
    {

if (typeof Parent === 'undefined')
    Parent = Klacc;

        var F = function() { };
        F.prototype = Parent.prototype;
        Child.prototype = new F();
        Child.prototype.constructor = Child;

Child._as = {};
if ( typeof Parent._as === 'object' ) {

var i;
for(i in Parent._as)
{
   Child._as[i] = Parent._as[i];
}
Child._as[Parent.name] = Parent.prototype;
}

        Child.super = Parent.prototype;
    };

Klacc.prototype.as = function(cl)
{
var cl = typeof cl === "function" ? cl.name : cl;
var ctor = this.constructor;
if ( ctor.name === cl )
{
  return this;
}
else if ( (typeof ctor._as === "object") && ctor._as[cl] )
{
  return ctor._as[cl];
}
return false;

}
Klacc.prototype.parentOf = function(cl)
{
  return this.as(cl).constructor.super;
}

function A() {  }
Klacc.extend(A)
A.prototype.init = function(){ /* A.prototype.init */
  if (++count < 100)
    console.log('A.prototype.init.apply', this);
  this.name = 'A';
}


function B(){  }
Klacc.extend(B,A)
B.prototype.init = function(){ /* B.prototype.init; this - instance of D */
  if (++count < 100)
    console.log('B.prototype.init.apply', this);
console.log('Parent Of B', this.parentOf(B));
this.parentOf(B).init.apply(this,arguments);

  this.extra = 'im B';
}

function C() {  }
Klacc.extend(C,B)
C.prototype.init = function(){ /* C.prototype.init; this - instance of D */
  if (++count < 100)
    console.log('C.prototype.init.apply', this);

console.log('Parent Of C', this.parentOf(C))
    this.parentOf(C).init.apply(this,arguments);

  this.extraC = 'mimimi';
}
c= new C

function D() {  }

Klacc.extend(D,C)

D.prototype.init = function(){ /* D.prototype.init */
  if (++count < 100)
    console.log('D.prototype.init.apply', this);
console.log('Parent Of D', this.parentOf('ags'));return;
    this.parentOf('D').init.apply(this,arguments);

}

d = new D

d.init()