You need to fix alot of issues before you attempt any further changes.
1. you are using a very old version of jQuery, Id advise you use 1.8.2
3. you have redefined the same functions over 5 times, why??
4. your html is malformed quite a bit, especially in content_1
i'd advise you run your current code through the w3c validator, fix the major issues first before continuing on.