Javaworld article on DWR
JavaWorld have published a good tutorial on using DWR. The article misses a few recent changes to DWR so you'll need to know about the following:
In place of, DWRUtil.showById("id"); you should use $("id").style.display = '';.
And in place of DWRUtil.drawTable(...) you should use DWRUtil.addRows(...).
The reason for the changes is that we are trying to concentrate on being a AJAX library and not a set of generic Javascript functions. So DWR will help you get data from a server using AJAX, but it won't help you mucking with CSS and so on. Other libraries can do that better.