Netscape 6, Part VI: Object-Oriented DOCJSLIB 1.2

This column is the seventh part of our series on Netscape 6. In this column we'll present another approach to browser-independence and apply it to DOCJSLIB 1.1. The modified library is DOCJSLIB 1.2. The new approach is to encapsulate browser-dependent functions as methods of a dedicated class, one per browser type. This scheme is based on the object-oriented design methodology. We'll bring you up to speed on understanding and applying the object-oriented terminology, buzzwords, and syntax. We'll teach you how to define methods and properties in a subclass, and how to inherit methods and properties from its superclass.

DOCJSLIB 1.2 supports the same three methods as DOCJSLIB 1.1 . The principles of DOCJSLIB 1.2 remain the same: hiding implementation details from the scripter, API-like (Application Procedural Interface) function interfaces, and browser-independence. The advantage of DOCJSLIB 1.2's browser independence over that of DOCJSLIB 1.1 is in its limited use of if-else statements (down to a single one). We demonstrate DOCJSLIB 1.2 with our traditional Tic-Tac-Toe game.

In this column, you will learn:

• How to use object-oriented design concepts
• How to inherit methods
• How to architect the include files
• How to write a browser sniffer
• How to create a browser-dependent subclass on the fly
• How to write a browser-independent superclass
• How to write a browser-dependent subclass
• How to write an application using DOCJSLIB 1.2

At this point, you may also view the code for:

• Tic-Tac-Toe board game
• Browser sniffer
• Creating a browser-dependent subclass on the fly
• Browser-independent superclass
• Browser-dependent subclass for IE4
• Browser-dependent subclass for IE5
• Browser-dependent subclass for NS4
• Browser-dependent subclass for NS6

Just copy from these files and paste to your own application. A ZIP file version of all DOCJSLIB 1.2 library files is also provided.

Next: How to use DOCJSLIB's principles