Can I call a js script method inside a C# dll project?

I have a c# dll project and I can use the classes in unity.
I have a lot of js code out side the dll.
My question is can I invoke these js or other c# files inside my dll project?

No (and Yes). You won’t be able to link with the Unity produced DLLs so your DLL project won’t be able to see them. You can of course use delegates or interfaces and pass objects between them that way (the interfaces would have to be defined by the DLL project).