WebObjects® Developer's Guide

Optimizing WebObjects Generated DHTML

You might have noticed that the DHTML we generated was not optimal. In particular, it didn't employ image preloading, which helps to improve the first impression of the rollovers.

In this section we'll look at adding image preloading to WORollover and then incorporate it into DynamicMovies.

Using WOJavaScript

Let's return to WORollover. Open the component in WebObjects Builder.

What we want to achieve in terms of HTML and JavaScript is something along the lines of the following:

						<script language=JavaScript>
						        image_U = new Image();
						        image_U.src = '/image.gif';
						        image_H = new Image();
						        image_H.src = '/imageH.gif';
						</script>
<a href="/index.html" onMouseOver="image.src=image_H.src;"
						onMouseOut="image.src=image_U.src;"> ...