Abstract: A browser-control script for controlling how refreshed data is rendered during a network data-session is provided. The browser control script comprises an instruction for establishing a second data-channel between a client and a data source, a data-communication function for transacting data over the second data-channel, an instruction for enabling selective data-rendering by the browser application, a selection function for selecting data elements to be refreshed and an instruction for predicting a new scroll position in a browser window. Once invoked, the browser-control script provides an automated control-routine for managing a data-refresh operation such that data re-rendering within the browser application only occurs when there are updated data elements ready for display, the re-rendering of the data specific to the updated data elements.