19. A method comprising: applying a transformation file on a hierarchical data file having first and second nodes to produce a first rendering file; rendering the first rendering file to show a rendered form having a first data-entry field associated with the first node of the hierarchical data file and a second data-entry field associated with the second node of the hierarchical data file; enabling a user to input data into the first data-entry field; changing the hierarchical data file by retaining the data in the first node of the hierarchical data file; applying the transformation file on the changed hierarchical data file to produce a second rendering file; determining a difference between the first rendering file and the second rendering file; attempting to map the difference on the first rendering file; producing a third rendering file, the third rendering file comprising a partial rendering file based on the difference if the map is successful and comprising a full rendering file if the map is not successful; rendering the third rendering file to show a second rendered form reflecting the change to the hierarchical data file; and enabling the user to input data into the second data-entry field.
19. A method comprising: applying a transformation file on a hierarchical data file having first and second nodes to produce a first rendering file; rendering the first rendering file to show a rendered form having a first data-entry field associated with the first node of the hierarchical data file and a second data-entry field associated with the second node of the hierarchical data file; enabling a user to input data into the first data-entry field; changing the hierarchical data file by retaining the data in the first node of the hierarchical data file; applying the transformation file on the changed hierarchical data file to produce a second rendering file; determining a difference between the first rendering file and the second rendering file; attempting to map the difference on the first rendering file; producing a third rendering file, the third rendering file comprising a partial rendering file based on the difference if the map is successful and comprising a full rendering file if the map is not successful; rendering the third rendering file to show a second rendered form reflecting the change to the hierarchical data file; and enabling the user to input data into the second data-entry field. 22. The method of claim 19 , wherein the hierarchical data file is written in XML.