I’ve been obsessing over the jQuery-menu-aim plugin and the “how did they do that” factor for a few days. Ben Kamens, the creator of the plugin, wrote a nice overview of this on his blog. He originally saw the fast menus on Amazon.com and got the nerd how did they do that bug.
In the article he says that Amazon.com uses linear algebra to solve this problem by creating a triangle between the menu item and the top & bottom of the sub-menu. This is a really smart approach because it accounts for how humans want to use a menu. That is, we want to go directly towards the sub-menu item that we want; We do not want to move directly over to the right without accidentally going up or down off of the item; We want to go directly towards that thing we want to click on and not fuss around. Nothing is more frustrating than having the menu disappear before you can click this thing.
So check out his tech breakdown of how they did that and if interested “git” the jQuery Menu Aim plugin. Cheers!