What does these lines of CSS do?

Question

In the following lines (from superfish):

ul.sf-navbar .current ul ul {
    top: -999em;
}

Does top: -999em have a special meaning? Why is the top set to a value that is not visible in the browser?

Someone is using an oddball property when there are better alternatives, that's what it means. — animuson, Nov 17 '11 at 18:00

score 2 · Answer 1 · answered Nov 17 '11 at 17:57

2

That would be so the subnavigation is "hidden" until it's parent is hovered over, then it will be shown.

answered Nov 17 '11 at 17:57

Damon Bauer

score 2 · Accepted Answer · answered Nov 17 '11 at 17:58

2

It's purpose is solely to keep any second-tier and higher menus from appearing automatically when the first-tier menu is displayed.

answered Nov 17 '11 at 17:58

simshaun

score 2 · Answer 3 · answered Nov 17 '11 at 17:58

2

I presume this is a drop-down menu that is set beyond the visible bounds using top: -999em; so that it can be changed via javascript/css to appear.

answered Nov 17 '11 at 17:58

ghoppe

3 Answers3