<script language=JavaScript>
var reEmail=/@.+\../;
var reHTML=/\<.|\>.$/;
var form = document.forms[ 0 ];

function validate(form) { 
if(!form.chislo.value) return feedback(form.chislo,"Не заполнено поле!");
	return true;
}
function feedback(element,msg){
	alert(msg);
	element.focus();
	return false;
}
</script>
<b>внесенные записи  удалят через:</b>
<form action="save.php"  method="post" onsubmit="return validate(this);">
 <input type="text" name="chislo" value="'.$val.'" size="5" maxlength="3"/> дней
 <input type="submit" name="submit" value="Сохранить" />
</form>