add additional functionality to ajax project

This will be a very quick project for someone who knows JavaScript. As you can see here: [login to view URL] I have a little app that pulls from a database. I use ajax to populate the 'trade' and 'category' field at the top of the page. The problem is that, after populating the page with the correct data, the 'category' dropdown needs to populate with the currently selected category. It does not right now. I need you to make it so that, after a page load where both trade and category has been selected, the chosen category is the 'selected' item in the category drop down, and also make it so that another category can be selected with a form submit on change. Also, I am not married to this AJAX code in any way -- If you have a better solution, lets use it! I need this done immediately, so please do not bid unless you can start work right away. Please let me know that you can start right away in your comments. Thanks for looking!