How to Scrape dropdown in form with postback event?

I'm new to https://webscraper.io/ and I can't seem to figure this rather simple scrape out. Below is the URL. On this page is a single dropdown that posts a value to a form (0-4) I need to select each item to be able to grab the text from a td of a table. Any idea?

dropdown : select#ctl00$ContentPlaceHolder1$DropDownList1

Url: http://rvreservations.gnfamarket.com/default.aspx

Hi
web scraper cant deal with dropdown button