Steps - "Own Code" - What is it ? can i wrote global javascript function ?

[veeco]

Hello,
i wondering, what and how to use "own code" under the steps panel ? any sample ?
i'm thingking about writing a global function that can be accessed anytime on a template, is it possible ? (for example, in every single task started i will add a predefined keys/variable, or create a function to calculate something that can be ask in any steps)

Thanks