Is there a external script language compatible with every platforms in unity?

Hello boys, I want an external script language that can be dynamically loaded from AssetBundle in textasset.

I have tried to use C# script but it seems that Assetbundle can not directly pack it in, but need to use tools like Assembly which is not supported in IOS.

Here, what I need is a language like LUA that can perform some exported functions that i provided in C#. I do not know is there a way to use build-in Javascript in unity to dynamically execute a string script. (If it can, maybe a solution).

Besides, I found a library UniLua but it runs very slow in my project with the feature coroutine, so i want to found other solutions, or have I make some mistakes in using UniLua?