function seaon() {
  document.getElementById("search_full").setAttribute('style','display: inline');
  document.getElementById("sea_on_butt").setAttribute('style','display: none');
  document.getElementById("sea_off_butt").setAttribute('style','display: table-row');
  //document.getElementById("search_fast").setAttribute('style','display: none');
};

function seaoff() {
  document.getElementById("search_full").setAttribute('style','display: none');
  document.getElementById("sea_off_butt").setAttribute('style','display: none');
  document.getElementById("sea_on_butt").setAttribute('style','display: table-row');
  //document.getElementById("search_fast").setAttribute('style','display: inline');
};

function val(form) {
  if (form.fulltxt.value=="") {
     alert("Nevyplnili jste vyhledávácí pole!\nSearch filed is emtpy!");
     form.fulltxt.focus();
     return false;
  }
  else if (form.fulltxt.value.length < 3) {
     alert("Musíte zadat alespoň 3 znaky!\nYou must enter minimum 3 characters!");
     form.fulltxt.focus();
     return false;
  } else {
   return true;
  }
};

//autor, nazev, words, rok_od, rok_do
function val1(form) {
  v_a = form.autor.value.length;
  v_n = form.nazev.value.length;
  v_w = form.words.value.length;
  v_od = form.rok_od.value.length;
  v_do = form.rok_do.value.length;
  if ((v_a > 2 ) || (v_n > 2) || (v_w > 2) || (v_od > 2) || (v_do > 2)) {
    return true;
    alert("OK");
  } else {
     alert("Nevyplnili jste ani do jednoho z vyhledávácích polí alespon 3 znaky!\n You haven't filled in at least 3 symbols in the search field!");
     return false;
  }
};