expanding menu

[brunette]

I have copied the code on the expanding menu from the website http://javascript.internet.com/navigation/expanding-menu.html . It worked well, however, the menu collapses back up and I then have to reopen it again. What do I have to do in order to keep the menu expanded until I click on another mainlink?

I need the sample menu on the website http://www.sense.org.uk/

Hope to hear from you asap.

Thanks