I have been trying to use a filter on my "I am trying to create my first website"-website, the problem is when I assign 2 or more class values.

The animations don't work on the proper way. 

I have been using

http://www.jscraft.net/plugins/filters.html

For an example of my problem please visit 

http://volhardinggoudswaard.nl/filmpje/Films.html (It's dutch)

If you select "Horror" or "Kinderfilm" you will be able to see it.

I hope someone can help me with my problem.

I'm kinda stuck at this point

Thanks!