I change hosting of my website, and currently try Ubuntu + LAMP as new web site platform. (Apache version is 2.2.22) For some webpages I use xmlhttprequest in _javascript_ function to get modification time of other pages using "Last-Modified" response header, but I found that for particular file names (at least containing ".html" and ".htm") after making "HEAD" (or "GET") request the "Last-Modified" header is missing among other headers. If I rename target file, say, from "a.html" to "a" or "
a.ht", "Last-Modified" presents and I finally get modification time of that file. It seems that "Last-Modified" response header is suppressed somewhere by Apache (probably due to optimization reasons), and the question is how to setup Apache to provide "Last-Modified" for any file name. Just note that the problem is observed with empty httpd.conf, as well as use of headers_module did not resolve the issue.
