hi,
not sure i totally understand your question -
but if you want to have an error message pop up if none of the checkboxes are filled in this can be done
a simple solution would be to just have a script that says if a = null and b = null and c= null and d = null then produce an error message saying "you must make a selection" or whatever
that would look something like
if( A.rawValue == "0" && B.rawValue == "0*"*) && C.rawValue etc..... {
xfa.host.messageBox("You must select a checkbox [or whatever].";
}
the above would produce an error popup if NO checkbox was ticked
not sure if thats what you need - hope so
you also said "The main question I've got about these is: Is there any AdobeReader version that gives a hint in the error message to which field is checked?"
this CAN be done - but im not sure what you want your form to do - you can use a script to tell someone that they have ticked the wrong box - so if they can only tick a combination of choice a and choice a OR choice b and choice b for example and they click a and b - you could have code to say you have selected a and b but you cant do that
-- if you give some more detail on what you want im sure someone on here can help - im happy to try
you also asked if - error message can be done by scripting --- short answer is yes --- an error message box is the easiest - it uses the "xfa.host.messageBox" function as demoed above
so once you work out your requirements (if x then y) you can place the code on a suitable event - (have not seen you form to suggest one) and simply have it say "hey fix up your choices for those checkboxes" (or whatever)
if you want to test the xfa.host.messageBox function try using a new blank form and putting a standard button on it - then put the messagebox function on the click event with your desired text (in the format above) - set to dynamic etc and click it in the preview - you'll see what you would get from a basic message box
the message box function an be customized but hopefully that will get you rolling.
good luck