If error in Node.js, how to tell app to run animation located in regular js files?

In my node.js files, if there is an error, I want an animation to occur which I have created in regular javascript files. But how do I communicate to them from the node.js files?

So for one function I have callback function that takes error as an argument in my node.js, and then I wrote "If (error) //do something" but what I want to do is run animation in the normal js files when I get the error. So how do I tell it to do that?

thnx

might be a nooby question but any help much appreciated

via koz