new date[3][11];
new dateString[11]="00/00/0000";
split(dateString, date,'/');

new day = strval(date[0]);
new month = strval(date[1]);
new year = strval(date[2]);

if(day < 1 || day > 31) SendClientMessage(playerid, -1 ,"Day can only be from 1 to 31.");
if(month < 1 || month > 12) SendClientMessage(playerid, -1,"Month can only be from 1 to 12.");
if(year < 1) SendClientMessage(playerid, -1,"Year can be less than 1.");

stock split(const strsrc[], strdest[][], delimiter)
{
    new i, li;
    new aNum;
    new len;
    while(i <= strlen(strsrc))
    {
        if(strsrc[i] == delimiter || i == strlen(strsrc))
        {
            len = strmid(strdest[aNum], strsrc, li, i, 128);
            strdest[aNum][len] = 0;
            li = i+1;
            aNum++;
        }
        i++;
    }
    return 1;
}