Creating a iPhone friendly drop down menu for a site?

Hello,

I recently created a website for a friend. The web site and the drop down menus work fine on most of the common PC web browsers like internet explorer, firefox, chrome etc. But the problem occurs when I visit the site using the iphone.

Everything else in the web site seems to be fine except the issue relating to the drop down menu as given below.

On the first tap on an item on the horizontal navigation bar, the secondary item list appears. However, before even I could select a sub-item on the secondary item list, I am taken to the page of the first sub-item in the secondary item list.

Please help me to resolve this issue and create a iphone friendly drop down menu for the site.

Thanks.