1. An update detecting system for detecting an update in a target file, the target file accessible by a server computer having a processing unit, and memory operatively coupled to the processing unit, comprising: a client computer having a central processing unit and memory operatively coupled to the central processing unit, the client computer and the server computer configured to communication over a communications network; the server computer configured to access the target file and transmit the target file to the server computer upon request by the client computer; a difference extractor configured to extract differences between text data included in said target file and text data included in a copy file obtained by copying said target file; a morphological analyzing unit configured to divide said differences into words to generate a word group, and configured to determine if one or more words in the word group matches a predetermined specific key word or if a group of words in the word group matches a regular expression; and a determining unit configured to determine that an update was is performed in said target file based on whether the morphological analyzing unit determined a match.