How to do a form check in Purchase?(Must fix)

As this is a must to fix it as user can cheat the system by
entering like 0.0000001 for the amount of lottery ticket to buy
as it clicked purchase actually it purchased one ticket but the user's points
is not deducted.... as for example
Ticket price : 200.00
Max Ticket per user : 10

that user just need to go thought the process and key in 0.000001 in the number of tickets to purchase and click purchase and done... it purchase one ticket but no points is deducted... and he repeat 10 times... he will brought 10 tickets without using a single point

so i suggest to put up a form check on the textbox like showing no decimal point is allow to keyed in
the textbox... but i don't know where is the coding at so donno where to add it

if textbox < 1 than pop up error or so
else normal steps
================================================== ================
Ok i done the fix !!!
you need to edit this file action.lottery.php in vbplaza folder

Paste this under
$action = vbplaza_action_check_for_flood($action);

// check the fieldvalue is it less than 1 if yes put it to 1
if (!is_numeric($action['ticketsamount']) || ($action['ticketsamount'] < 1))
{
// force it to at least 1 ticket sold
$action['ticketsamount'] = 1;
}
else
{
// force the maximum down some
if ($action['ticketsamount'] > 50)
{
// force the amount down to 50
$action['ticketsamount'] = 50;
}
}

[CMX_CMGSCCC]

Thanx for the fix, I have added this fix into v1.5.7

-CMX