It uses javascript, and I haven't often seen anything more complicated.
Look at http://www.bmw-motorrad.co.uk/uk/en/...avigation.html with javascript enabled and View/Source code and take a look. There are also several javscript files to download to look at as well.
If I were you, stick to normal links with different colors for the hover state.
a:link { color: #de7007; } /*unvisited link orange*/
a:visited { color: #008080; } /*visited link teal*/
a:hover { color: #996633; } /*hover link dark brown*/
a:active { color: #800080; } /*active link purple*/
Code downloaded to my PC will be deleted in due course.
WIN7; IE9, Firefox, Opera, Chrome and Safari for Windows; screen resolution usually 1366*768.
Also IE6 on W98 with 800*600 and IE8 on Vista 1440*900.