get value from TXDataWebEntityField

Yes, that is true. COD_SET is the associated object, it's a Javascript object, as I mentioned. You get the underling object using Value property and then you can do properly further processing with it.

TheCODSETObject := TJSObject(wdGrpCOD_SET.Value);
OnePropertyOfCODSETObject := string(TheCodeSETObject['COD_SET'];