// top of script

new Timer[MAX_PLAYERS];//global variable

forward KilometriParcursi(playerid);//forward it

public KilometriParcursi(playerid) {
    //do what you want here
    return 1;
}

public OnPlayerConnect(playerid) {
    Timer[playerid] = SetTimerEx("KilometriParcursi", 1000, true, "i", playerid);  
    return 1;
}

public OnPlayerDisconnect(playerid, reason) {
    KillTimer(Timer[playerid]);
}