checkData function posted below does not consider a date entered such as 03/27c/2000. The c will cause it to crash. Here is the fix.
function checkData($mydate) {
list($yy,$mm,$dd)=explode("-",$mydate);
if (is_numeric($yy) && is_numeric($mm) && is_numeric($dd))
{
return checkdate($mm,$dd,$yy);
}
return false;
}