function img_switch (which) {
  elem = document.getElementById(which);
  elem.src = '/images/zamow.png';
  //alert(elem.src);
}

function img_back (which, what) {
  elem = document.getElementById(which);
  elem.src = what;
  //alert(elem.src);
}

function check_form (what) {
  alert(this.form.email.value);
}