I am writing a dev tool and I have no experience with Objective-C or Xcode, currently. I am trying make it cross platform and therefore, I will be using the native programming language for each platform that it supports. I am thinking about using Javascript for the user to script in. I am wondering if Objective-C is the best language for this or are there any better options for cross platform development. Though, please bear in mind that I can use different programming languages for the different platforms supported. I am thinking about using a Python and/or Java for the supported desktop platforms including Win, Mac, Linux. And Objective-C for iPhone and iPad.

To summarise my question, how can I use Javascript code in Objective-C, even if that means it uses third party libs. I don't mind it, if its compiled with Objective-C or interpreted. Compiled Javascript is probably preferable for better performance. Btw I only want to use objective-c for iOS.