Stopping processing inside an event

I have a question similar to this post:

http://forums.adobe.com/message/3287875

I am inside a click event (button push) in Adobe Forms in a JavaScript routine.  I want to exit conditionally.  The above message had no repy and other searches did not find what I need.

Example in pseudo-code:

----- data.SF1.BTN_SHOW::click: - (JavaScript, client) ---------------------------------------------

var x = 1;

xfa.host.messageBox ("Before");

if (x==1) {

  return;

}

xfa.host.messageBox ("After");

If x is not 1, I want to see two popups, if it is 1 only the first one.  I tried 'return', 'exit', 'break', 'quit' (and a few other possible commands).  Since I am not inside a function, 'return' does not appear to work.

Thanks in advance.  I find the forums hard to navigate, so I hope I get an answer and find this post...

Regards,

Wolfgang