how to check input text before POST operation? it must be numbers only
<form method="post" action="credit.php">
Сумма кредита: <input type="text" name="sum"> <br />
первый взнос: <input type="text" name="pv"> <br />
Срок: <input type="text" name="srok"> <br />
Процентная ставка: <input type="text" name="percent"> <br />
<input type="submit">
</form>
sorry for my bad english.