A method, system, apparatus, and computer program product are presented for processing Web page documents to determine the availability or unavailability of in-line resources within a Web page. A transaction monitor receives an indication from a Web browser that a Web page has been retrieved, after which the transaction monitor examiners a document object model maintained by the Web browser for the retrieved Web page. The transaction monitor determines whether the document object model indicates that a set of one or more in-line resources in the retrieved Web page is unavailable, and in response, the transaction monitor generates an unavailability indicator for an unavailable in-line resource. The unavailability indicator may be signaled through an appropriate software event, placed in a statistical database, or presented on a display as graphical information for a user of the transaction monitor.