bejjj on "[Theme: Twenty Eleven] submenu on ipad/iphone"

I found the problem: I would like to make a submenu like this:

PARENT => link to nothing
--- SUBMENU1 => link to a page
--- SUBMENU2 => link to a page

How to make a parent that links to nothing? (just a parent menu)?
For this, I used a "link-type menu" with empty URL, this was the problem!
How is the regular way to do a parent that doesn't link to anything ?