1. A method comprising: at a windowless web browser configured to execute on a controller on a network router or a network switch and to parse a Hypertext Markup Language (HTML) document, the web browser further configured to communicate with a set of application program interfaces (APIs) that provide access to controllable data and control plane features of the network router or the network switch: receiving the HTML document including HTML network service tags each including a command to cause a corresponding network action to be taken in connection with the network router or the network switch; parsing the HTML network service tags; determining, based on the parsing, the command to cause the network action to be taken in connection with the network router or the network switch; and issuing the determined command for each HTML network service tag to a corresponding one of the APIs, which in turn cause the network action to be taken in connection with the network router or the network switch.