Building Web Applications with UML Second Edition

Custom JavaScript Objects

Even though it is not an object-oriented environment, JavaScript does provide a mechanism for encapsulation, or 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. Using the dot operator, four custom properties are defined and assigned values.

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 example, the following ...