Check

[#Paper]

how i can check if is the 1° time that a player join?

[Castillo]

set a data on his account or something like that.

[#Paper]

set a data on his account or something like that.

if getAccountData(source, "mspserver.newplayer") == "yes" then 
outputChatBox("No New Player!") 
else 
outputChatBox("No New Player!") 
end 

like this?

but if the player join for 1° time the server can't find the accountData, and returns the errer, so?

[Castillo]

account data uses player ACCOUNT not player ELEMENT.

getPlayerAccount(source) 

[DakiLLa]

You could just do

if not getAccountData( getPlayerAccount( player ), "dataNameYouWantToCheck" ) then 
  outputChatBox( "Joined for the first time" ) 
  setAccountData( getPlayerAccount( player ), "dataNameYouWantToCheck", "yes" ) 
else 
  outputChatBox( "Welcome back on my server" ) 
end 

since getAccountData returns false if no data was found with such key.

edit: and notice that thing that Solidsnake14 said.

[#Paper]

You could just do

if not getAccountData( getPlayerAccount( player ), "dataNameYouWantToCheck" ) then 
  outputChatBox( "Joined for the first time" ) 
  setAccountData( getPlayerAccount( player ), "dataNameYouWantToCheck", "yes" ) 
else 
  outputChatBox( "Welcome back on my server" ) 
end 

since getAccountData returns false if no data was found with such key.

edit: and notice that thing that Solidsnake14 said.

ty, it works