How can I check if an object is an instance of a specific class?

To check if an object is an instance of a specific class, use the `instanceof` operator with the class name. For example, if you have a class called `MyClass`, you can use `instanceof MyClass obj` to check if `obj` is an instance of `MyClass`. This works even if the class is defined later in the code. If the class doesn't exist, `instanceof` will return `false`.