Ajax in Action

Chapter 9. Dynamic double combo

This chapter covers

• The client-side JavaScript
• The server side in VB .NET
• Data exchange format
• Refactoring into a reusable component
• Dynamic select boxes

If you have ever shopped for a new shirt online, you may have run into the following problem. You pick the shirt size from one drop-down list, and from the next drop-down list you select the color. You then submit the form and get the message in giant red letters: “Sorry, that item is not in stock.” Frustration sets in as you have to hit the back button or click a link to select a new color.

With Ajax we can eliminate that frustration. We can link the selection lists together, and when our user selects the size option from the first list, all of the available ...