How to get the instance name in JavaScript?

Question

If I create a class like this:

function MyClass(input){
  // construct something;
  var myInstanceName = ???
}

I'll need the name of the instance when creating an instance...

var MyInstance = new MyClass("Make Something");

Need to know myInstanceName (="MyInstance" in this case) because there is a method that creates buttons and the "onclick" must call a method of this instance.

I tried "this.name" but it returns undefined... How do I get this value?

EDIT: Here is a tested working example:

function MyClass(WhereGoesTheButton){
    this.myName = "Test"; // <-- here is the issue
    this.idButton = WhereGoesTheButton;
    //
}
MyClass.prototype.createButton = function(){
    document.getElementById(this.idButton).innerHTML = '<button id="myId" onclick="'+this.myName+'.callBack(this);">Press Here</button>';
}
MyClass.prototype.callBack = function(who){
    alert("Button "+who.id+" has been pressed!");
}
var Test = new MyClass("testArea");
//
function ini(){
    Test.createButton();
}

Just put it in a page with body onload ini() and some div to create the button.

It works, but alternatives with better practices are welcome!

EDIT 2: this will do the job, although we still got no name of the instance:

var MyClassId = 0;
function MyClass(WhereGoesTheButton){
    this.myButtonId = "MyClass"+String(MyClassId);
    MyClassId++;
    this.idButton = WhereGoesTheButton;
    //
}
MyClass.prototype.createButton = function(){
    var me = this;
    document.getElementById(this.idButton).innerHTML = '<button id="'+this.myButtonId+'" >Press Here</button>';
    document.getElementById(this.myButtonId).addEventListener("click", function(e){ me.callBack(this); }, false);
}
MyClass.prototype.callBack = function(who){
    alert("Button "+who.id+" has been pressed!");
}
var Test = new MyClass("testArea");
//
function ini(){
    Test.createButton();
}

Answer 1

Simple code example:

 function Parent(){
        // custom properties
    }

    Parent.prototype.getInstanceName = function(){
        for (var instance in window){
            if (window[instance] === this){
                return instance;
            }
        }
    };

    var child = new Parent();

    console.log(child.getInstanceName()); // outputs: "child"

Answer 2

Need to know myInstanceName (="MyInstance" in this case) because there is a method that creates buttons and the "onclick" must call a method of this instance.

Why do you need the variable name for that? Your method can reference the current instance with this.

However, inside a click handler this will be the clicked element. Assuming you're bind the event somewhat like this:

someElement.addEventListener('click', this.someMethod, false);

... you can change it to:

var that = this;
someElement.addEventListener('click', function(e) {
    that.someMethod()
}, false);

There are other possible solutions too, like bind and the EventListener interface.