A method for processing an emergency alert message, EAM, by a primary device, PD, in a broadcast system, comprising: discovering, by a companion screen, CS, manager in the PD and using a first application program interface, API, transmitted from the emergency alert, EA, manager in the PD to the CS manager, a companion device, CD; receiving, by the CS manager, a CD information message from a launcher in the CD, requesting, by the EA manager, the CS manager to launch a companion application in the CD, based on information for the CD included in the received CD information message, wherein the companion application is used for receiving the EAM from the PD and displaying information on the received EAM; triggering, by the CS manager, the launcher to launch an emergency alert, EA, application by using a second API; generating (1043, 1045) a websocket channel based on a websocket server in the PD receiving a websocket channel open message for requesting to generate the websocket channel, from each of the EA manager and the companion application in the CD; and transmitting the EAM to the companion application via the generated websocket channel, wherein the EAM includes: information indicating an identifier of the EAM, information indicating strings of the EAM, information indicating a uniform resource identifier, URI, for rich media content used to support the EAM, wherein the rich media content includes at least one of an image or a video, information indicating a date and time when the EAM is fired, expiration time information indicating an expiration time of the EAM, and priority information indicating a priority of the EAM, and wherein if the priority of the EAM is higher in a priority of each of at least one other EAM which is already displayed, the EAM is displayed on the at least one other EAM. discovering, by a companion screen, CS, manager in the PD and using a first application program interface, API, transmitted from the emergency alert, EA, manager in the PD to the CS manager, a companion device, CD; receiving, by the CS manager, a CD information message from a launcher in the CD, requesting, by the EA manager, the CS manager to launch a companion application in the CD, based on information for the CD included in the received CD information message, wherein the companion application is used for receiving the EAM from the PD and displaying information on the received EAM; triggering, by the CS manager, the launcher to launch an emergency alert, EA, application by using a second API; generating (1043, 1045) a websocket channel based on a websocket server in the PD receiving a websocket channel open message for requesting to generate the websocket channel, from each of the EA manager and the companion application in the CD; and transmitting the EAM to the companion application via the generated websocket channel, wherein the EAM includes: information indicating an identifier of the EAM, information indicating strings of the EAM, information indicating a uniform resource identifier, URI, for rich media content used to support the EAM, wherein the rich media content includes at least one of an image or a video, information indicating a date and time when the EAM is fired, expiration time information indicating an expiration time of the EAM, and priority information indicating a priority of the EAM, and information indicating an identifier of the EAM, information indicating strings of the EAM, information indicating a uniform resource identifier, URI, for rich media content used to support the EAM, wherein the rich media content includes at least one of an image or a video, information indicating a date and time when the EAM is fired, expiration time information indicating an expiration time of the EAM, and priority information indicating a priority of the EAM, and wherein if the priority of the EAM is higher in a priority of each of at least one other EAM which is already displayed, the EAM is displayed on the at least one other EAM.