How to call a function from event to script file?

I'm trying to figure out, I added a function in event sheet "callPrompt" and I added a function in script file:

function yourName() {
 var person = prompt("Please enter your name", "Chuck Norris");
}

Thanks Ashley! I haven't seen this action before.

Also I have another question, is there an expression to get return value from function in script file?

No problem, I just figured it out I managed to create a new function with defined return value and call an expression like that:

runtime.setReturnValue(yourName());