If possible, JavaScript converts each parameter passed to a PODS method into the type the method expects. When a parameter’s type is s, the method expects a non-null string, and so JavaScript converts the JavaScript value null to the string "NULL", then converts the undefined value to the string "UNDEFINED". When a parameter’s type is S, the method expects a string that may be NULL. In that case, if JavaScript code passes either of the JavaScript values null or undefined for a parameter, when M-Business Client calls the underlying PODS method it passes a null pointer for the parameter.