Return msg.payload from dashbord without angular

I know this is weird but I am integrate existing code (not angular) to make a new dashboard widget. I want to send my variable back to Red Node payload, so I try

                initController: function($scope, events) {
					$scope.$watch('urm_json', function() { //Watch object_json and send payload if changed
						$scope.send({payload: urm_json});

Where urm_json is my variable. However this code doesnot work.
Could anyone help me, tks alot

Comment advises to use convertBack for this purpose
[convertBack] - callback to convert the message from front-end before sending it to the next connected node


Tks for your reply

I still dont get convertBack do, but I solve this with angular way, it s less painful than finding road no one go