A document previewing system includes a display device including a user interface and a document previewing engine coupled to the display device. The document previewing engine is configured to download an outline of a document including outline features and filler content in between the outline features. The filler content replaces secondary content of the document. The document previewing engine is further configured to display the outline on the display device, and download the secondary content corresponding to an outline feature in response to a user navigating to the outline feature and the outline feature displaying on the display device for a period of time.