Script to compare folders content comparison between two directories and compare files in text, html, xml and other formats. and display difference between changes, deleted, non-existing, and identical content.
On a website? You don't do that sort of thing on a site. On the computer itself, you could use any of a number of programs. Which one depends on whether you want to compare which files are in the 2 directories, or the contents of files. (On a Linux box, diff is probably best for comparing file contents.)