// JavaScript Document
function isEmail(email, class_bad, class_good)
{
   var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
   var address = email.value;
   if(reg.test(address) == false)
   {
      email.className = class_bad;
      return false;
   }
   email.className = class_good;
   return true;
}

function isEmpty(field, class_bad, class_good)
{
   strfield = field.value
   if (strfield == "" || strfield == null || !isNaN(strfield) || strfield.charAt(0) == ' ')
   {
      field.className = class_bad;
      return false;
   }
   field.className = class_good;
   return true;
}

function changeSubmit()
{
   button = document.forms['form'].elements['send'];
   komentarz = isEmpty(document.forms['form'].elements['comment_text'], "tresc_bad", "tresc");
   autor = isEmpty(document.forms['form'].elements['autor'], "podpis_bad", "podpis");
   mail = isEmail(document.forms['form'].elements['autoremail'], "mail_bad", "mail");

   if(komentarz == true && autor == true && mail == true)
      return true;

   return false;
}