Beginning Web Development, Silverlight, and ASP.NET AJAX

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CHAPTER 11 ■ AJAX APPLICATIONS AND EMPOWERING THE WEB USER EXPERIENCE
Finally, you need to wire up the event handlers for the buttons, allowing navigation
through the images. It’s pretty straightforward—you simply increment or decrement the
current picture ID and then call ShowPic with the new ID:
function DoPrev()
{
currentPic--;
ShowPic(currentPic);
}
function DoNext()
{
currentPic++;
ShowPic(currentPic);
}
And that’s it. You now have an Ajax page with forward (and backward) caching of
images. You can streamline this page if you like—when you think about it, Ajax isn’t necessary
for the ShowPage call—you could simply construct an tag from the current
pic, but it is good to understand the technique, as you will use it in more complex apps.
You can see the application in action in Figures 11-8 and 11-9. The latter is the result
of clicking the >> button shown in Figure 11-8. As you run the application, you’ll see how
quickly the pictures update and render.
Figure 11-8. Running the forward-caching Ajax application