Abstract: An improved change-detection tool detects only relevant changes within Internet web pages on the world-wide-web. Changes back to an earlier version of a web page are not relevant and do not cause the user to be notified. Only changes to a new, unique version of the web page generate a user notification. After the user finishes registering the web page by specifying the URL and the user's e-mail address, the change-detection tool periodically retrieves the web-page at the specified URL and generates a checksum or signature to determine when to send a notification to the user. Signatures from several older versions of the web page are stored in a history table. When a new signature for a re-fetched page matches the most-recent signature at the top of the stack in the history table, no change has occurred. When the new signature matched any of the older signatures in the history table, the detected change is not unique and notification is not made even though a change has occurred.

Abstract: A change-detection web server automatically checks web-page documents for recent changes. The server retrieves and compares documents one or more times a week. The user is notified by electronic mail when a change is detected. The user registers a web-page document by submitting his e-mail address and the uniform resource locator (URL) of the desired document. The document is fetched and the user can select text on the page of interest. Non-selected text is ignored; only changes in the selected text are reported back to the user. Thus changes to less relevant parts of the document are ignored. The document is divided into sections bounded by hyper-text markup-language (HTML) tags. A checksum is generated and stored for each HTML-bound section. Storage requirements are reduced since only checksums are stored rather than the original documents. During periodic comparisons a fresh copy of the document is retrieved, divided into HTML-bound sections and checksums generated for each section.

Abstract: An improved change-detection tool detects only relevant changes within Internet web pages on the world-wide-web. Changes back to an earlier version of a web page are not relevant and do not cause the user to be notified. Only changes to a new, unique version of the web page generate a user notification. After the user finishes registering the web page by specifying the URL and the user's e-mail address, the change-detection tool periodically retrieves the web-page at the specified URL and generates a checksum or signature to determine when to send a notification to the user. Signatures from several older versions of the web page are stored in a history table. When a new signature for a re-fetched page matches the most-recent signature at the top of the stack in the history table, no change has occurred. When the new signature matched any of the older signatures in the history table, the detected change is not unique and notification is not made even though a change has occurred.

Abstract: A change-detection tool detects significant changes in numerical fields within internet web pages on the world-wide-web. A user identifies web-page web pages by specifying the web page's URL. The user then highlights one or more numeric fields on the web-page web page. The numeric fields' values are extracted to cells on a spreadsheet displayed to the user. The user enters parameters and formulas into unused spreadsheet cells. The formulas operate on the numeric values extracted from the web page to the spreadsheet's cells. The user also enters notification limits or conditions that are based on the results of the formulas. The notification conditions indicate when a change notification is to be e-mailed to the user. After the user finishes registering the web-page web page, the change-detection tool periodically retrieves the web-page web page at the specified URL and re-calculates the formulas and determines if the notification conditions have been met.

Abstract: A distributed-client change-detection tool detects changes in Internet web-page documents on the world-wide-web. To register a web page for change detection with a change-detection server, a user specifies the web page's URL. A client-side change-detection application is downloaded to the user's client from the change-detection server. The server assigns a date and time for the client to perform change detection. At the assigned time and date, the client fetches a new copy of the web page and compares it to an archived copy to detect changes. When the client detects a change, it sends a notification with the URL to the server. The server verifies that the change has not already been reported by another user's client and then notifies all users of the registered web page. As more users are registered for a web page, change detection is performed more frequently. The most popular pages with tens of thousands of registered users are checked every few minutes.

Abstract: A change-detection web server automatically checks web-page documents for recent changes. The server retrieves and compares documents one or more times a week. The user is notified by electronic mail when a change is detected. The user registers a web-page document by submitting his e-mail address and the uniform-resource locator (URL) of the desired document. The document is fetched and the user can select text on the page of interest. Non-selected text is ignored; only changes in the selected text are reported back to the user. Thus changes to less relevant parts of the document are ignored. The document is divided into sections bounded by hyper-text markup-language (HTML) tags. A checksum is generated and stored for each HTML-bound section. Storage requirements are reduced since only checksums are stored rather than the original documents. During periodic comparisons a fresh copy of the document is retrieved, divided into HTML-bound sections and checksums generated for each section.