I basically took a Super NES emulator and glued it to a web browser. This means the game can now talk to the browser and the browser can talk to the game. Then I did the same with an NES emulator and then a Game Boy/Game Boy Color/Game Boy Advance emulator. For more information about why I did this and what it's useful for, see here.
Note that I originally designed these for my own personal use, so I can't guarantee that these will work for you or that they'll run smoothly for you. These are Windows only - I don't have the knowledge or skill to make Mac versions. But maybe someone can use the source code to make some.
NOTE: To switch plugins, edit "setup.txt" to point to the plugin you want loaded and then re-run the emulator.
The NES Wanderbar might stick on a blank white page the very first time you run it. If you close the program and run it again, it seems to fix the problem.
I've included many plugins with each Wanderbar version. Most plugins are stored in Lua files in each sidebar directory. I'll provide documentation on these later on, but it's all pretty simple and straightforward stuff that you can figure out by checking a few of the existing plugins.
I had trouble coming up with a name for this weird thing I created, so I called it my "sidebar thingie" for about a year. Eventually I chose a random name just to finally give it a name. The "Wanderbar" is named after my cat Wander who happened to be in the room at the time. Her name, in turn, comes from the main character of the Shadow of the Colossus video game. I also have a cat named Zuul... I wonder if I should've called it the Zuulbar instead.
You can find me on Twitter here. I was hesitant to release these Wanderbar programs because they were designed specifically for my personal computer setup, and I lack the time to offer troubleshooting assistance. I also secretly hope that a better programmer than me can take this idea and do it better and/or incorporate it with even more emulators.