1. A data processing method comprising controlling a computer to address at least one predetermined element in a structured document, comprising the steps of: when the structured document having said at least one predetermined element addressed by predetermined addressing information is modified, inputting the structured document to analyze the modification and storing an analysis result in a memory; reading the analysis result from the memory; and updating the addressing information according to the analyzed modification so that the addressing information addresses at least one corresponding element or corresponding elements in the modified structured document.