function name_match(user_id, user_realname) {
    var dbref = firebase.database().ref();
    var namesref = dbref.child("names");
    namesref.on("value", function(snapshot) {
        snapshot.forEach(i => {
            if(i.key == user_id && i.child("realname").val() == user_realname) {
                return true;
            }
        });
    });
    return false;
}

function name_match2() {
    var user_id = document.getElementById("user-id").value;
    var user_realname = document.getElementById("user-realname").value;
    if(!name_match(user_id, user_realname)) return -1;
    return 0;
}