Replying to How To Get Menus Where Clikcing On A Link Opens A New Box, Instead Of A Page

I am trying to create a menu system where when a user clicks on a link, instead of directing to another page, a new div opens containing further information and links in it, which then direct to other pages. In more traditional types of menus, a simple hover over a link would open a list of menus but there I have two distinct issues.
FIrst of all, I don't need just a list of links. I need a box (a div) that can be styled and that can have simple text in it. It could contain images, and other links. It should scroll along the page, and not as a separate entity (I don't want it to look like a spammy promotion where everything except the box darkens).
Second, I need it to respond to the clikc and not to the hover. I need it to open only when a user clicks on a link. Furthermore, a small close button on the box itself, that closes it will aslo be helpful.
Is there someway I can do it. Will I have to use Javascript. I don't know where to start?
To elaborate things a little, I must tell that I am using a wordpress based website so if there is any plugin available for this purpose, it would make the job really easy.

I have seen examples of such link systems and I definitely know that it is possible. One good example is Phonearena.com. When you go to their website, at the top of the content there is a navigation bar. When you click on the "Mobiles" or "tablets" link, instead of being carried to another page, you will see that a sort of box appears that contains further links and information in it. There are images in the box and there are links that carry the user to other pages. The box doesn't contain any close button but when you clikc anywhere outside the box, it just disappears. A very fine system indeed.

An interesting thing is that when you hover over the "mobiles" link, at the bottom of your browser, the target of the link appears to be a different page but when you click on the link, instead of going to a different page, you get further information on the same page. I really liked that system and I am planning a good use of it on my website, but I don't know how to replicate it.
I hope it won't be illegal..... LOL