In this paper web sites are considered the object of several analyses, focused on their structure and their history, with the purpose of supporting maintenance activities. Structural information may help understanding the organization of the pages in the site, while history analysis provides indications on modifications that do not correspond to the original design or that produce undesirable effects.
A tool was developed to implement the analysis of web site structure and evolution. Its application to some examples downloaded from the Web highlights several areas where the extracted information can improve the control on the maintenance phase and provide valuable support.