Netscape 6, Part VII: Object-Oriented DOCJSLIB 3.1

This column is the eighth part of our series on Netscape 6. In this column, we'll extend our browser-independent library, DOCJSLIB 1.2, to more applications and more functions. The modified library is DOCJSLIB 3.1. The approach of DOCJSLIB 3.1 is the same as that of DOCJSLIB 1.2: 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, as we have introduced in Column 77, Netscape 6, Part VI: Object-Oriented DOCJSLIB 1.2.

DOCJSLIB 3.1 supports 12 methods, only two of them were supported in DOCJSLIB 1.2:

• getSrc()
• setSrc()
• setPosFromLeft()
• setPosFromTop()
• setZposition()
• setVisibility()
• doThisCommandEveryIntervalMS()
• getWindowWidth()
• getWindowHeight()
• getPageScrollLeft()
• getPageScrollTop()
• findHighestZ()

The principles of DOCJSLIB 3.1 remain the same: hiding implementation details from the scripter, API-like (Application Procedural Interface) function interfaces, and browser-independence. We demonstrate DOCJSLIB 3.1 with a compound application that includes Tic-Tac-Toe, popout elements, and page watermarks -- all in a single page. Load the page and play the game now.

In this column, you will learn:

• How to structure your application
• How to use DOCJSLIB 3.1 in programming Tic-Tac-Toe
• How to use DOCJSLIB 3.1 in programming popout elements
• How to use DOCJSLIB 3.1 in programming page watermarks

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

• Tic-Tac-Toe, popout elements, and watermarks application
• Browser-independent superclass object
• Internet Explorer 5.x subclass object
• Netscape 6 subclass object
• Internet Explorer 4.x subclass object
• Netscape Navigator 4.x subclass object

Just copy from these files and paste to your own application. A ZIP file version of all DOCJSLIB 3.1 library files was also provided.

Next: How to structure your application