Необязательное поле для обратной связи

<form  method="post" id="sendmail" name="sendmail" action="">
<div class="pheading"><h2>Обратная связь</h2></div>
<div class="baseform">
    <table class="tableform">
            <tr>
            
            <td><input type="hidden" name="recip" value="1"></td>
        </tr>
        <tr>
            <td class="label">
                Ваше имя:<span class="impot">*</span>
            </td>
            <td><input type="text" maxlength="35" name="name" class="f_input" /></td>
        </tr>
        <tr>
            <td class="label">
                Тема:<span clas>*</span>
            </td>
            <td><input type="text" maxlength="45" name="subject" class="f_input" /></td>
        </tr>

            <tr>
            <td class="label">
                Ваш E-Mail:<span class="impot">*</span>
            </td>
            <td><input type="text" maxlength="35" name="email" class="f_input" /></td>
        </tr>
        
        <tr>
            <td class="label" valign="top">
                Сообщение:
            </td>
            <td><textarea name="message" style="width: 380px; height: 160px" class="f_textarea" /></textarea></td>
        </tr>
        <tr>
            <td class="label">
                Введите код:<span class="impot">*</span>
            </td>
            <td>
                <div><span id="dle-captcha"><img src="/engine/modules/antibot/antibot.php" alt="Включите эту картинку для отображения кода безопасности" width="160" height="80" /><br /><a onclick="reload(); return false;" href="#">обновить, если не виден код</a></span></div>
                <div><input type="text" maxlength="45" name="sec_code" style="width:115px" class="f_input" /></div>
            </td>
        </tr>
        
            
    </table>
    <div class="fieldsubmit">
        <button name="send_btn" class="fbutton" type="submit"><span>Отправить</span></button>
    </div>
</div>
<input name="send" type="hidden" value="send" />
</form><script language="javascript" type="text/javascript">
<!--
$(function(){

    $('#sendmail').submit(function() {

        if(document.sendmail.subject.value == '' || document.sendmail.message.value == '') { 

            DLEalert('Заполните все необходимые поля', dle_info);
            return false;

        }

        var params = {};
        $.each($('#sendmail').serializeArray(), function(index,value) {
            params[value.name] = value.value;
        });

        params['skin'] = dle_skin;

        ShowLoading('');

        $.post(dle_root + "engine/ajax/feedback.php", params, function(data){
            HideLoading('');
            if (data) {
    
                if (data.status == "ok") {

                    scroll( 0, $("#dle-content").offset().top - 70 );
                    $('#dle-content').html(data.text);    
    
                } else {

                    if ( document.sendmail.sec_code ) {
                       document.sendmail.sec_code.value = '';
                       reload();
                    }

                    if ( document.getElementById('recaptcha_response_field') ) {
                       Recaptcha.reload(); 
                    }

                    DLEalert(data.text, dle_info);

                }
    
            }
        }, "json");

      return false;
    });

});

function reload () {

    var rndval = new Date().getTime(); 

    document.getElementById('dle-captcha').innerHTML = '<img src="/engine/modules/antibot/antibot.php?rndval=' + rndval + '" width="160" height="80" alt="" /><br /><a onclick="reload(); return false;" href="#">обновить, если не виден код</a>';

};
//-->
</script></div>    </div>
        <div class="clr"></div>