Active Message Content

Perhaps the most interesting aspect of SurfIt! is its ability to download Tcl/Tk scripts and execute them in a safe slave interpeter. Scripts written to be executed in this manner are known as applets. A safe interpreter prevents the applet from interfering with the user's computing environment.

Applets may be used to make a new capability available to the user, to perform special effects on a Web page or to pre-process forms before they are submitted.

A HTTP server should require no modifications to serve Tcl applets. The only configuration aspect that you should check is that your daemon knows that the .tcl file extension indicates documents of type application/x-tcl.

Demo Applets

I've prepared a few demonstration applets to show both the capabilities/possibilities of SurfIt! applets, as well as serving as examples of how to write applets.

Two very simple applets: one with almost no semantics, and one with little more.
Applets get certain information supplied to them.
This applet will eat your hyperpage's words. Notice how it does not disappear when you load a new hyperpdocument.
This applet is an animated hyperpage.

Security

An important consideration of the SurfIt! browser is the security of the user's computing environment. Various aspects of this topic have been considered and tested.