1. A data processing system comprising: a private resource; a connection to a public network; a hardware processor configured to process a public script instance and a distinct private script instance of a scripting engine while providing access to the private resource; and a memory configured to provide a browser environment, the browser environment configured to enable execution of: (i) the public script instance of the scripting engine, including allowing access to the public network when the public script instance of the scripting engine does not require access to the private resource; and (ii) the private script instance of the scripting engine as a plug-in to the browser, the private script instance of the scripting engine requiring access to the private resource including allowing access to the private resource when the access to the public network is denied; wherein the browser is configured with a data communication plug-in interface to allow communication from the public script instance of the scripting engine to the private script instance of the scripting engine, and to prevent communication from the private script instance of the scripting engine to the public script instance of the scripting engine unless there is a prior approval; and wherein only the private script instance of the scripting engine comprises a scripting API configured to enable access to the private resource.