tungsten wrote
My guess would be,
subroutineName() - calls method in current class
classInstanceName.subroutineName() - calls method in specified class
className.subroutineName() - calls function or constructor in className
 
You are correct.
For readers who may not be conversant with object oriented terminology, 
classInstanceName is the name of a variable of type 
className. As in:
    var Thing aThing;
    do aThing.foo();    // call method foo in Thing class
--Mark