javascript url hashtag to existing working solution

I have a list of results that is being filtered when items are picked in dropdown lists. The problem is that when the user goes through a link on this page and then returns using the back button - then the dropdown lists are still showing the last selected items but the search results are showing the "initial" search results -> before the ajax "filter data" calls were made. I need someone to add a #hash tags solution so that the "latest" search results will show even though the back button is being used to get to the page.