How to navigate doPostBack page numbers?

Describe the problem.
Trying to navigate a page with javascript links. There is First 1 2 3 4 .... 23 24 25 Last,
Each page has elements which are scrapable if I eliminate page navigation, but then there is no way to select more than the first page. When using any of the naviagation styles to select the page, it will simply open the url, then close the url... It wont even see the first page.

Url: https://app.oregonstudentaid.gov/

Sitemap:

23

{id:"sitemap code"}

Unfortunately, this site uses older tech (aspx) and WS often cannott deal with aspx links.

However, some sections of this site offer PDF downloads. e.g. https://app.oregonstudentaid.gov/Catalog/Default.aspx
(Button for "Full Catalog")

PDF data extraction is a whole different beast though.