METHOD, USER TERMINAL, AND WEB SERVER FOR PROVIDING SERVICE AMONG HETEROGENEOUS SERVICES

A method of providing a service among heterogeneous services may include verifying whether a second web application associated with an external web service is installed in a user agent, when data of the external web service is requested from a first web application executed in the user agent, requesting key information to be used for accessing the requested data from a first server providing a web service associated with the first web application, when the second web application is installed in the user agent, receiving the key information from the first server, and accessing the requested data existing on the second web application, using the received key information, in the first web application.