How to access a C# script variable or function in javascript ?

I am trying to access an instance of a file create in c# script from js . It arise error that script name is an unknown identifier .
thanx

Your UnityScript and C# files can’t see each other during compilation; however, scripts in your “Plugins” or “Standard Assets” folders will be compiled before other scripts, allowing them to be seen in other languages during later compilation steps.

More info here.

If you’re trying to access a C# script from JS, you can put the C# script in one of the folders named above.