Behaviour of back button on ajax and non-ajax page with the same url

Behaviour of back button on ajax and non-ajax page with the same url

I have got two versions of content (ajax and non-ajax) at one url. One
version is with renderred layout for non-ajax requests and the second
ajax-version is just the content itself without the layout. The problem is
that browsers (chrome/firefox) seems not to differentiate between
ajax/non-ajax requests when fetching pages from cache If I click on back
button. There are situations where I load the non-ajax version then I do
some browsing and then when I return back (by clicking back button
repeatedly) I get the ajax ("unformatted") version because that is the
version stored currently in the cache. Is this a known issue? Do I need to
differentiate ajax vs non-ajax requests in urls e.g. by ?ajax=1?