CSS/jQuery 4 tiered horizontal navigation bar

[Knoxx]

I want to make a 4 level nav bar says like below:Item1 Item2 Item3 Item4 Item5item1a item1b item1c item1d item1eitem1a1 item1a2 item1a3 item1a4item1a1a item1a1bSo basically i got 5 main items, and each item have sub-items. The example above is when the item1a1b been selected and landed on its page.Any though?

Thanks and happy new year!