Can I run a script in real time on a browser game?

I would like to know if there is any way to have like 2 “icons” on a website page, one with the web player(the game) and another with lines of code. And as I change the code, the game is updating in real time, or at least through a button or something. Is it possible?Something like this:

All Unity players don’t have a mono compiler included, so by default you can’t change any of your code at runtime. The easiest way is to use a dynamic scripting language like LUA. One implementation is UniLUA which has been optimised for Unity.