How can we access value of an archer field into custom object code ?

Hi Guys,

I have a query regarding inclusion of archer's field into custom object code

Problem Description:- for example we have a vale list type field "test" in an application. this field "test" holds two value X & Y. now I want to add a custom object into layout. Code of this custom object include a button and an action upon clicking of this button. so when I click on this button a pop up(alert function of JS) should be display with the current value of "test" field.

How can I call Archer's field into custom object code through java script??