Classes Inheritance Problem

I've discovered the following problem while building an APP:

/* Code Start **************************/
// Definition
function cClass_prototype_prototype()
{
this.array = new Array;
this.className = "cClass_prototype_prototype";
}

function cClass_prototype()
{
this.className = "cClass_prototype";
}

cClass_prototype.prototype = new cClass_prototype_prototype;

function cClass1()
{
this.className = "cClass1";
}

function cClass2()
{
this.className = "cClass2";
}

cClass1.prototype = new cClass_prototype;
cClass2.prototype = new cClass_prototype;

oClass1 = new cClass1();
oClass2 = new cClass2();

// Testing

alert(oClass1.array)
alert(oClass2.array)

oClass1.array.push(1);

alert(oClass1.array)
alert(oClass2.array)

/* Code End ****************************/

If you will execute this code you will see that pushing an value into
the first class instance array property cause changing value of the
second class instance array property.

Is it possible to have array values not connected to each other?
I would like to avoid defining "array" property in cClass1 and cClass2
(in this case it would work the proper way) and have them defined only
in third-level parent class cClass_prototype_prototype.