I know a spider cannot read JS but could it read the script on this page http://www.dynamicdrive.com/dynamicindex17/switchcontent.htm since the actual content is in a DIV class and not hidden in the JS?
Using http://womans-net.com/cgi-bin/spiderview/spiderview_da.pl it looks as if it can be read. Anyone think I'm reading the results wrong? P.S. You can view the script in question without viewing the source it's a script page.
You should check a lynx-viewer to see what spiders see, try this one: http://www.yellowpipe.com/yis/tools/lynx/lynx_viewer.php
Or test it with a new page, link to it and see what comes up in the cache. Then you would be sure if SEs read it.