Can a callback function that belongs to a JavaScript object prototype access the object members?

How can callback function that belong to a JavaScript object prototype access the object members? the callback can't be closure, ev开发者_如何学编程erything must be defined as follows:

function Obji(param){
   this.element = param;
}

Obji.prototype.func(){
   database.get("someKey",this.cb);
}

Obji.prototype.cb(){
   //here I would like to access this.element
}

---

database.get("someKey",this.cb.bind(this));

.bind, ES5 shim for older browsers

---

In javascript this always points to the object on which the function is invoked or the global object if it's not invoked on anything. Can you do it this way?

Obji.prototype.func = function(){
   var ref = this;
   database.get("someKey", function(){ref.cb()});
}