What is the way to let Google crawl my all pages which changes according to a DropDownList's selected value.

I want to let Google crawl my page which contents are changing according to DropDownList's Selected Value. I am changing "Title of Page" with the DropDownList's value. It works fine. But Google only crawls that page with DropDownList's Default value and ignores other values of DropDownList. I am not passing any parameter in this way in URL. So how can I tell Google to crawl my page with changing its content according to DropDownList's value similar to passing URL parameters.