Wow that is messed up. Hover on the first item in the dropdown then move your cursor off to the left and the last link (Contact) in the main list pops up.
Scripting should just enhance the page and not leave it in a non working state if is disabled. Your menu is using display:none; to hide the sub ul which makes it keyboard tabbing impossible. When your js is disabled your dropdown stops working too.
I would look into to using something like Superfish that is built off of a pure css dropdown then enhanced with js for visual effects.