function check_email(address)
{
  var regex = /^[a-zA-Z0-9._-]+@([a-zA-Z0-9.-]+\.)+[a-zA-Z0-9.-]{2,4}$/;

  return regex.test(address);
}

function check_form()
{
  /* email address check */
  var oEmail = document.getElementById('feedback_menu_email');

  if (oEmail == null)
    return false;  
  
  var address = oEmail.value;

  if (check_email(address) == false) {
    /* change background color of email text filed*/
    oEmail.style.background = '#aaaaaa';
    oEmail.focus();

    return false;
  } else {
    oEmail.style.background = '';
  }

  /* message text area check */
  var oMsg = document.getElementById('feedback_menu_msg');

  if (oMsg == null)
    return false;

  var msg = oMsg.value;
  if (msg == null || msg == '') {
    /* change background color of textarea*/
    oMsg.style.background = '#aaaaaa';
    oMsg.focus();
    
    return false;
  } else {
    oMsg.style.background = '';
  }

  return true;
}