function valideren(value)
{
   var ValidChars = "0123456789";
   var IsNumber=true;

 
   for (i = 0; i < value.length && IsNumber == true; i++) 
      { 
      Char = value.charAt(i); 
      if (ValidChars.indexOf(Char) == -1) 
         {
         IsNumber = false;
         }
      }

if((value == '0') || (IsNumber == false))
	{
		alert ("Gelieve uw aantal correct in te geven!");
		return false;
	}
else
	{
		return true;
	}
}