You can request some stuff, i.e.
HTML Code:
temp.response = sendListerRequest("checkguildexists", temp.gName);
if (temp.response[1][1] == true) {
player.sendMessageBox(N_("That gang name can't be created, it exists on Graal already. Contact an admin if you're the owner of this gang."));
return false;
}
etc, research this stuff