Fixed code that could make "hasRequiredFielfd" function crash
Fixed code that could make "hasRequiredFielfd" function crash

imkevinyang/jsonform,yklykl530/jsonform,globocom/jsonform,nishant8BITS/jsonform,capriza/jsonform,iainbeeston/jsonform,jsonform/jsonform,globocom/jsonform,tagyangyang/jsonform,widgetworks/jsonform,capriza/jsonform,ulion/jsonform,suricactus/jsonform,suricactus/jsonform,mrthan/jsonform-rails,nishant8BITS/jsonform,joshfire/jsonform,imkevinyang/jsonform,joshfire/jsonform,jsonform/jsonform,ulion/jsonform,widgetworks/jsonform,tagyangyang/jsonform