For Using Both Drop Down and Vertical forms, i found the best solution for me was to keep both the .js separate, and simply rename one of them, so that all occurrences of the functions/divs were named different from the Drop Down version. In my case, I used "sidemenu" for the function. And "sidemenudiv" for the div names. I also made sure all my side menu array elements were named "side1", "side2" etc...
For Multiple Class Function:
dropmenuobj.className=istop? topmenudiv : sidemenudiv
your in page link:
hope this helps others who may not have found any other ways.
<a href="#" onMouseover="sidemenu(this, event, side2, '150px', 1)" onMouseout="delayhidemenu()"