New Member - Trying to Replicate Existing Page

Hi all,

I wanted to see if someone could give me a summary of the types of elements/languages that are used in a specific page that I found. I have read a few intro books on web development, but still have a lot to learn. I am trying to create a website that is similar to the product customization page below:

I cannot link a webpage as a new user so please go to knockaround . com, then click custom near the top right, and then hit fort knocks.

It would be super helpful if someone could explain what language this was built in and different aspects that I would need to learn to replicate something close to it. Specifically, the parts that I am interested in are how to set up the drop down boxes to customize a product and then that drives different parts of the image that is displayed.

Any help at all would be appreciated. Thank you!

It's just a set of 5 images that are displayed on top of each other. The image URL for each piece is changed dynamically using JavaScript when a selection is made in the drop down boxes.