attribute(send,class,"btn btn-dark") :- somefeedback
attribute(send,class,"btn btn-disabled") :- ~somefeedback
attribute(send,disabled,false) :- somefeedback
attribute(send,disabled,true) :- ~somefeedback

somefeedback :- field(feedback,X)

select(X,Y) & ~matches(Y,"^\s*$") ==> field(X,Y)
select(X,Y) & field(X,Z) ==> ~field(X,Z)

innerhtml(msg,"Great to meet you") :- ~morethanonce
innerhtml(msg,"We appreciate your feedback") :- morethanonce

innerhtml(f(X),Y) :- field(X,Y)
holds(f(X),Y) :- field(X,Y)
value(X,Y) :- field(X,Y)
holds(X,Y) :- field(X,Y)

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

click(send) ==> submitted

style(form,display,"") :- ~submitted
style(form,display,"none") :- submitted

style(thankyou,display,"") :- submitted
style(thankyou,display,"none") :- ~submitted

click(morefeedback) ==> ~submitted & morethanonce
click(morefeedback) & field(feedback,X) ==> ~field(feedback,X)