10. A method according to claim 1 , wherein the tool code comprises code for creating a display effect by altering at least one of the objects and parameters of the internal representation of at least one of the content documents.
10. A method according to claim 1 , wherein the tool code comprises code for creating a display effect by altering at least one of the objects and parameters of the internal representation of at least one of the content documents. 11. A method according to claim 10 , wherein altering at least one of the objects and parameters comprises modifying the internal representation of the at least one content document to add content to the screen document.