1. A computer-implemented method comprising: providing an application programming interface running in a web browser on a computer to receive a call from an event handler to process a detected user navigation event on a web page, wherein content navigation rules (CNRs) characterize nodes of a document-object-model (DOM) of the web page as a sequence of one or more logical paths through the web page when rendered by the computer, and wherein the CNRs are associated with respective augmented user interface (AUI) functionalities that are tailored to different types of users; in response to receiving the call, requesting a user preference file from a remote server; receiving, from the remote server, the user preference file and an AUI component API identified in the user preference file; and in response to receiving the user preference file: processing the detected user navigation event by: identifying a CNR corresponding to the detected navigation event; and calling, in the web browser, an AUI component application via the received AUI component API to invoke an AUI on the computer, the AUI having the respective AUI functionality associated with the identified CNR.