9. A computer-implemented web browser-based document editing system, comprising a computing device configured to: display an editing surface defined by an electronic model of the document, wherein the editing surface comprises a visual rendering of the electronic model, wherein a portion of the visual rendering of the electronic model is hidden from the user; receive an entry of a character to the editing surface; determine a location to display the character on the editing surface by determining a size of an off-screen display area including the character; and transfer at least a part of the hidden portion to the displayed editing surface when the user provides a scrolling input wherein the hidden portion is different from the off-screen displayed and the off-screen display is not transferred to the displayed editing surface.
9. A computer-implemented web browser-based document editing system, comprising a computing device configured to: display an editing surface defined by an electronic model of the document, wherein the editing surface comprises a visual rendering of the electronic model, wherein a portion of the visual rendering of the electronic model is hidden from the user; receive an entry of a character to the editing surface; determine a location to display the character on the editing surface by determining a size of an off-screen display area including the character; and transfer at least a part of the hidden portion to the displayed editing surface when the user provides a scrolling input wherein the hidden portion is different from the off-screen displayed and the off-screen display is not transferred to the displayed editing surface. 15. The system of claim 9 , wherein the computing device is further configured to: determine a position for an item in the visual rendering based on sizes and positions of other items in the electronic model, wherein the position for the item in the visual rendering depends on the location of the cursor in the electronic model; and place the item at the determined position on the editing surface.