JavaScript task is not evaluating

Hello,
I have created a simple javascript task.while i’m executing the process,getting following error

org.camunda.bpm.engine.ProcessEngineException: Cannot find serializer for value ‘Untyped value ‘[object global]’, isTransient = false’.

Can any one please help me with this.

javascriptBpmn.bpmn (4.4 KB)

Thanks,
Sagari