-Is a method for sending json data without worrying about cross -domain issues.
-Jsonp does not use the xmlhttprequets object to avoid problems,
-because if you are requisting file from anothe domain can problems, due to cross-domain policy.
-Json uses the script tag because when requesting an external script from another domain does not have this problem.
-Transfere of information between two or more differing security domains.