function check() {
 if (document.feedback.name.value=="") {
  alert("Fill in 'FULL NAME' field!");
  document.feedback.name.focus();
  return false;
 };
 if (document.feedback.email.value=="") {
  alert("Fill in 'E-MAIL' field!");
  document.feedback.email.focus();
  return false;
 };
 if (document.feedback.message.value=="") {
  alert("Fill in 'MESSAGE' field!");
  document.feedback.message.focus();
  return false;
 };
 document.feedback.submit.value='Sending...';
 document.feedback.submit.disabled=true;
}