Answer by Alexis Abril for How can I refer to a parent from a child?

I'd also move showAlert onto the prototype, so you're not creating a new function in memory every time you instantiate ParentControl.

var ParentControl = function() {    this.childControl = new ChildControl(this);};ParentControl.prototype.showAlert = function() {  console.log('hello');};var ChildControl = function(parent) {  parent.showAlert();};var parentControl = new ParentControl();