What is this mouseover popup called?

[enchant]

In many sites, I'm seeing an effect that I'd like to put in some of my pages, but I simply don't know what it's called or what the technology is. Perhaps it isn't even javascript.

When you hover over something (without clicking), a window pops up (similar to a tooltip), but it might have an image enlargement, or a small formatted page of information. I've even seen some that had scroll bars for long pages.

What is this called?

[RonPK]

I'm not aware of a specific name for such a technique.

Basically one needs to toggle the value of CSS

display

property (to 'block' or 'none') that belongs to an element with the 'popup' content. That can be triggered by either the

:hover

pseudo-class (in CSS) or a

onmouseover

event handler in JavaScript.

[Mr Bo Jangles]

I think it's powered by snap-dot-com and it's becoming a bit annoying - one commentator said he was getting afraid of moving his mouse, lest a pop-up ambushed him!

[enchant]

I think that it's annoying when used by advertisers (like the advertisements aren't annoying enough...

I've seen it used very productively, though. There's a stock photography website that displays a screen of 100px thumbnails, and it will pop up a 400px image if you hover over the thumbnail. This is SO much faster than having to click on the thumbnail and then go back to the previous page.