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How feasible is a browser that uses something like Lua, Python or Ruby as its scripting language instead of JS? Also, how stupid is this idea (ignoring any "incompatibility with JS pages" situations)?
You could transpile different languages into JS. So you write in the language of your choice, transpile it to JS, then send the transpiled JS to the user’s browser. You could possibly do the same thing but use webasm as well.