15. A method at an electronic device for rendering structured documents for display, the method comprising: while a display screen of the electronic device is in a first orientation, rendering a structured document for display, the structured document including a plurality of content elements each having corresponding content, by generating a model including a hierarchical arrangement of the plurality of content elements and applying to the model said corresponding content and any style directives included with the structured document for said content elements to provide a rendered structured document, the style directives included with the structured document not being associated with a particular orientation of the display screen; outputting said rendered structured document to a display screen of the electronic device; while said rendered structured document is being displayed at the display screen, detecting a change in orientation of the display screen to a second orientation; further rendering the structured document for display by: identifying a subset of said plurality of content elements, the subset excluding one or more of the content elements that are advertisements and that were included in the structured document when the electronic device was in the first orientation; altering the model previously generated to include only those ones of the subset of said plurality of content elements; and applying to the model thus altered any corresponding content to provide a further rendered structured document, the rendered document being a reader-style document having fewer advertisements than the first rendered document; and outputting the further rendered structured document to the display screen in response to said detecting.
15. A method at an electronic device for rendering structured documents for display, the method comprising: while a display screen of the electronic device is in a first orientation, rendering a structured document for display, the structured document including a plurality of content elements each having corresponding content, by generating a model including a hierarchical arrangement of the plurality of content elements and applying to the model said corresponding content and any style directives included with the structured document for said content elements to provide a rendered structured document, the style directives included with the structured document not being associated with a particular orientation of the display screen; outputting said rendered structured document to a display screen of the electronic device; while said rendered structured document is being displayed at the display screen, detecting a change in orientation of the display screen to a second orientation; further rendering the structured document for display by: identifying a subset of said plurality of content elements, the subset excluding one or more of the content elements that are advertisements and that were included in the structured document when the electronic device was in the first orientation; altering the model previously generated to include only those ones of the subset of said plurality of content elements; and applying to the model thus altered any corresponding content to provide a further rendered structured document, the rendered document being a reader-style document having fewer advertisements than the first rendered document; and outputting the further rendered structured document to the display screen in response to said detecting. 17. The method of claim 15 , wherein the structured document comprises a webpage, and the plurality of content elements includes text content elements, and the subset of said plurality of content elements includes only the text content elements.