One of my pages contain three levels of a collapsible menu (JS + CSS from mycssmenu.com). There are a dozen first level items displayed to users, each one with various second level items, and finally a lot of third level items, each one containing a related link.This generates a lot of internal links (300+). Because of SEO should I change the way the collapsible menu is displayed to reduce link amount? What do you suggest?  I would like to avoid users to have to open a new page just to only see what are third level items and eventually follow one of its links. 
Collapsible menu and amount of links in a web page
seo;css;javascript