field(subscribe,yes)

  select(X,Y) & ~matches(Y,"^\s*$") ==> field(X,Y)
  select(X,Y) & field(X,Z) ==> ~field(X,Z)
  deselect(X,Y) ==> ~field(X,Y)
  value(X,Y) :- field(X,Y)
  holds(X,Y) :- field(X,Y)

  style(ok(X),display,"") :- field(X,Y)
  style(ok(X),display,"none") :- countofall(Y,field(X,Y),0)

  innerhtml(newuser,X) :- field(name,X)
  style(welcome,display,"") :- somename
  style(welcome,display,"none") :- ~somename
  somename :- field(name,X)

  field(msgtype,Z) :- worksheetanchor(Z)

  okay :- field(name,X) & field(email,Y)% & field(message,Z)
  click(send) & okay ==> ok
  click(send) & ~okay ==> ~ok