Handling when callback is undefined or null.
Handling when callback is undefined or null.

ScotterC/drakov,notonthehighstreet/drakov,supersheep/drakov,notonthehighstreet/drakov,blech75/drakov,StefanoDalpiaz/drakov,Aconex/drakov,galkinrost/drakov,supersheep/drakov,blech75/drakov,PelegR/drakov,marcelogo/drakov,groyoh/drakov,galkinrost/drakov,marcelogo/drakov,groyoh/drakov,rixo/drakov,rixo/drakov,PelegR/drakov,ScotterC/drakov,StefanoDalpiaz/drakov,khaliddermoumi/drakov,Aconex/drakov,khaliddermoumi/drakov