New website help, (newbie.....sorry)

Hello all i just completed a basic website and can't find any local help , here is my site:

I know its a little juvenile but hey its my first one. I used Komposer/photoshop cs4 and a lot of youtube video tutorials and created this from basic (0) knowledge so any info would be helpful.

I am trying to create a basic simple no frills cascading parts lookup like they have on here:

I have read they use javascript?. Is there a program that allows me to set up a parts configuration with these simple folders and all upfront data, I have been looking for quite sometime and have had no luck, Thanks