Building Web Applications with UML

Custom JavaScript Objects

Even though JavaScript is not a pure object-oriented language, it does provide a mechanism for encapsulation. Encapsulation is the ability to package and to hide data in an object. In JavaScript, you can create an instance of a generic object and assign it properties and even methods. For example, in the following JavaScript a generic object instance called cartLineItem is created. The dot operator is used to define and to assign values to four custom properties:

cartLineItem = new Object();
cartLineItem.productID = 'MG1234';
cartLineItem.productName = 'MGB Roadster (1935)';
cartLineItem.qty = 1;
cartLineItem.unitPrice = 36000;

The cartLineItem instance can be used later by any JavaScript with a reference to it. For ...