I'm planning on using popup boxes on my project page to define terms and provide help. So I've been working out the kinks on this page. I dissected an example from Flybase, as well as a script from Dynamic Drive. What I ended up with, you see on this page. Another great resouce is WebMonkey, where I read a tutorial on DHTML.
Notice how the popup boxes move with the mouse. This is because J/S is capturing the mouse movement. This also allows me to position the popups no matter where the link is on the page. Also, I put in some code that checks how close you are to the side of the page. If you're too close, the position of the popup is adjusted accordingly. This idea is from the popups at Flybase.
You can also use these popups with a picture, i.e.
If you encounter any problems with these popups, or if you have any suggestions for improving the code, please tell me.