6. The method of claim 4 , wherein the candidate field and the other information are not both located in a same table on at least one of the second version of the web page and the first version of the web page.
4. The method of claim 3 , wherein the identifying the candidate field includes evaluating a location of the candidate field relative to locations of other information on the second version of the web page with the first version of the web page containing the first unsuccessfully retrieved field.