Object Oriented JS - OO Programming - Create Search Objects Or Arrays

Trying to figure out OO programming for JavaScript and I'm totally lost.

Here's what I'm trying to do:

I'm posting search data to a PHP form to run a query on a database.

The structure is sort of like this:

So I'm thinking I need to create search objects or arrays. Initially, I thought I could do something like this:

Code:

This doesn't seem to work. It says object not defined whenever I try to do something.

I've also tried creating a JSON object like this:

Code:

This will allow me retrieve the data like I want to:

Code:

The problem is I can't figure out how to add data to the JSON object without manually typing it in. I need to be able to loop through form elements on my HTML page and set them to these variables. I'm using jQuery and doing something like this:

Code: