function Person(name, surname) {
	this.name = name;
	this.surname =  surname;
}

function Developer(name, surname, knownLanguage) {
	Person.apply(this, arguments);
	this.knownLanguage =  knownLanguage;
}

var johnSmith = new Developer("Jan", "Kowalski", "JavaScript");

console.log(johnSmith.name);			// wynik:	"Jan"
console.log(johnSmith.surname);			// wynik:	"Kowalski"
console.log(johnSmith.knownLanguage );		// wynik:	"JavaScript"


johnSmith instanceof Developer;		// wynik:	true
johnSmith instanceof Person;		// wynik:	false
johnSmith instanceof Object;		// wynik:	true