How does this behave in prototype chain method calls? Does it refer to the instance or the prototype?

When you call a method defined on a prototype (e.g., instance.method()), the this inside the method refers to the instance object, regardless of where the method resides in the prototype chain. This is because the method is invoked as a property of the instance, even if the property is inherited. Example: function Person(name) { this.name = name; } Person.prototype.greet = function() { console.log(this.name); }; const alice = new Person('Alice'); alice.greet(); // 'Alice' (this refers to alice instance, not Person.prototype).