----------------------- CLIENT SIDE
addEventHandler("onClientResourceStart", getResourceRootElement(getThisResource()), showLogin )
function onClicked()
    player_username = guiGetText( GDI['username:edit'])
    player_password = guiGetText( GDI['password:edit'])
    triggerServerEvent("checkplayer",getLocalPlayer(),player_username,player_password)
    outputChatBox("Wysylam trigger")
end
----------------------- SERVER SIDE

function zapytanie( player_username,player_password )
outputChatBox("TRIGGER DZIALA")
-- GDI['username:edit'] it is a player wrote login
-- GDI['password:edit'] it is a player wrote password
end
addEvent( "checkplayer", true )
addEventHandler( "checkplayer", getRootElement(), zapytanie )