hi developers,

As am not a pro in service-now need help I have variables section on my task form or am using third party application......so when am fetching the details using the application in my response am not able to get the values of the  variable field and for that i wrote a business rule  

try {
var r = new sn_ws.RESTMessageV2('HTTP_REST_API', 'POST');
r.setStringParameterNoEscape('sys_id',current.sys_id);
r.setStringParameterNoEscape('description',current.description);
r.setStringParameterNoEscape('short_description',current.short_description);
r.setStringParameterNoEscape('instance_id',current.variables.instance_id); // variable field 

var response = r.execute();
var responseBody = response.getBody();
var httpStatus = response.getStatusCode();
}
catch(ex) {
var message = ex.getMessage();
}

as you can see in the above code the instance field value is needed but am not getting where am going wrong...please help me with this

thanks in advance!!