1. A method of paginating an electronic document comprising: receiving, by a processor of a user electronic device comprising a viewport for viewing the electronic document, the electronic document in an unpaginated format; generating, by the processor, a preliminary layout for the electronic document in the unpaginated format, the preliminary layout having a layout width that is equivalent to a viewport width of the viewport of the user electronic device, the viewport configured to display the electronic document, wherein generating the preliminary layout comprises: generating a Document Object Model (DOM) tree comprising first byte offset information for a first visual element of the electronic document in the unpaginated format and second byte offset information for a second visual element of the electronic document in the unpaginated format; determining the second byte offset information for the second visual element indicates an element width that is greater than a width threshold; reducing the element width of the second visual element to less than or equal to the width threshold; and generating a second DOM tree with updated second byte offset information in response to the reducing; computing, by the processor, a final layout for the electronic document in a paginated format based at least in part on: reviewing the preliminary layout to identify a plurality of horizontal areas to assign one or more page breaks without a visual element spanning multiple pages of the electronic document; and assigning a page break to one or more of the plurality of horizontal areas; rendering, by the processor, a current page in the viewport in accordance with the final layout, wherein the current page excludes the first visual element comprising at least a portion excluded by the page break from display within the viewport; and after changing from the current page to a new page, rendering, by the processor, the new page without re-computing the final layout of the electronic document, wherein the new page includes the first visual element.