person1 = new Object();
person1.firstName = " Frodo ";
person2 = new Object();
person2.firstName = " Zarg ";
var tt = function(e) {document.write(e+this.firstName + "<->" + firstName);}
person1.sayName = tt;
person2.sayName = tt;
person1.sayName(" 1");
person2.sayName(" 2");
var firstName = "MainLine";
tt(" 3");
1 Frodo <->undefined 2 Zarg <->undefined 3 MainLine <-> MainLine

This style of object fails to abstract the values inside the object. Function tt was able to get the value “Zarg” thru a peculiar and undocumented interpretation of “person2.sayName(" 2")” which means something different from “(person2.sayName)(" 2")”. But there is a better way.