Your operator(s) should be intelligent enough to figure out that the same controls do the same things, in that case. There really is no one HTML L&F -- it's dependent on the browser, OS, toolkit (in some cases), and possibly other factors. If you really need to have a common look and feel, then find a UI toolkit, plaf (for Java / Swing), and/or customization set, whichever happen(s) to be applicable, that is interfaceable to every system that needs to have a UI. Another alternative is to simply write the UI into one separate frontend, then put the other programs behind some sort of command line interface and use pipes (same box) or sockets (different boxes).

Just my 2%$USD...