JavaScript® Bible, Sixth Edition

Chapter 55. Application: Decision Helper

IN THIS CHAPTER

• Multiple frames

• Multiple-document applications

• Multiple windows

• Persistent storage (cookies)

• Scripted image maps

• Scripted charts

The list of key concepts for this chapter's application looks like the grand finale to a fireworks show. As JavaScript implementations go, the application is, in some respects, over the top, yet not out of the question for presenting a practical interactive application on a web site without any server programming.

The Application

I wanted to implement a classic application often called a decision support system. My experience with the math involved here goes back to the first days of Microsoft Excel. Rather than design a program that had limited appeal (covering only one possible decision tree), I set out to make a completely user-customizable decision helper. All the user has to do is enter values into fields on a series of screens; the program performs the calculations to let the user know how the various choices rank against each other.

Although I won't be delving too deeply into the math inside this application, you will find it helpful to understand how a user approaches this program and what the results look like. The basic scenario is a user who is trying to evaluate how well a selection of choices measure up to his or her expectations of performance. User input includes:

• The name of the decision

• The names of up to five alternatives (people, products, ideas, and so on)

• The factors or features of concern ...