Question

var Shape = Class.create(new Element("div", {
    "class": "shape"
}), {
    //constructor of Shape
    initialize: function () {

    }
})

Shape class inherit from an instance of Element, all what I want to get to know is, how can I refer to this instance in constructor of Shape if I can?

Answer 1

http://jsfiddle.net/r585d/

Use this to refer to the Element instance inside Shape constructor:

this.constructor.prototype

Alternatively, you could do this (Since it doesn’t make sense for a shape to inherit from element):

var Shape = (function() {
    var elem = new Element("div", {
        "class": "shape"
    });
    return Class.create({
        initialize: function() {
            //refer to elem here    
        }
    });
})();