function kontrola(formular) {

  if (formular.message.value=="") {
    alert("Musíte vyplnit vzkaz!");
    formular.message.focus();
    return false;
  }
  else if (formular.odesilatel.value!="")
  {
	  if (window.RegExp) {
    re = new RegExp("^[^@]+@[^.]+\..+$");
    if (!re.test(formular.odesilatel.value)) {
      alert("Zadaná adresa není správnou adresou elektronické pošty!");
      formular.odesilatel.focus();
      return false;
    }
  }
  }

  else {
    return true;
  }
}

function openWindow() {
    newwin=window.open('','okno','menubar=0,location=0,scrollbars=yes,width=540,height=540,resizable=1,top=0');
}

  function testSubmit(form) {
  
  if (form.jmeno.value == "")
     alert("Musíte zadat jméno !");
  else if (form.email.value == "")
     alert("Musíte zadat e-mail !");
  else if (form.dotaz.value == "")
     alert("Musíte zadat dotaz !");     
  else
        form.submit();
  }
  
  function zmenaDat(form) {

   if (form.varianta[0].checked) {
       form.origmaxwidth.value=280
       form.origmaxheight.value=400
       form.thumbmaxwidth.value=170
       form.thumbmaxheight.value=110
   }
   else if (form.varianta[1].checked) {
          form.origmaxwidth.value=500
          form.origmaxheight.value=500
          form.thumbmaxwidth.value=160
          form.thumbmaxheight.value=102
   }
  }
  

function onImageA() {   document.septik.src = "images/ikonky/do_septikuOn.jpg"; }
function offImageA() {  document.septik.src = "images/ikonky/do_septiku.jpg"; }
function onImageB() {   document.tuky.src = "images/ikonky/na_tukyOn.jpg";}
function offImageB() {  document.tuky.src = "images/ikonky/na_tuky.jpg";}
function onImageC() {   document.potrubi.src = "images/ikonky/do_potrubiOn.jpg"; }
function offImageC() {  document.potrubi.src = "images/ikonky/do_potrubi.jpg"; }
function onImageD() {   document.kompost.src = "images/ikonky/do_kompostuOn.jpg"; }
function offImageD() {  document.kompost.src = "images/ikonky/do_kompostu.jpg"; }
function onImageJ() {   document.cov.src = "images/ikonky/do_covOn.jpg"; }
function offImageJ() {  document.cov.src = "images/ikonky/do_cov.jpg"; }
function onImageK() {   document.sok.src = "images/ikonky/septiksokOn.jpg"; }
function offImageK() {  document.sok.src = "images/ikonky/septiksok.jpg"; }
function onImageM() {   document.neu.src = "images/ikonky/neutralizerOn.jpg"; }
function offImageM() {  document.neu.src = "images/ikonky/neutralizer.jpg"; }

function onImageE() {   document.septic.src = "images/ikonky/for_septicOn.jpg"; }
function offImageE() {  document.septic.src = "images/ikonky/for_septic.jpg"; }
function onImageF() {   document.grease.src = "images/ikonky/against_greaseOn.jpg";}
function offImageF() {  document.grease.src = "images/ikonky/against_grease.jpg";}
function onImageG() {   document.pipe.src = "images/ikonky/for_pipeOn.jpg"; }
function offImageG() {  document.pipe.src = "images/ikonky/for_pipe.jpg"; }
function onImageH() {   document.composting.src = "images/ikonky/compostingOn.jpg"; }
function offImageH() {  document.composting.src = "images/ikonky/composting.jpg"; }
function onImageI() {   document.wwtp.src = "images/ikonky/for_wwtpOn.jpg"; }
function offImageI() {  document.wwtp.src = "images/ikonky/for_wwtp.jpg"; }
function onImageL() {   document.shock.src = "images/ikonky/septicshockOn.jpg"; }
function offImageL() {  document.shock.src = "images/ikonky/septicshock.jpg"; }
function onImageN() {   document.neut.src = "images/ikonky/neutralizerOn.jpg"; }
function offImageN() {  document.neut.src = "images/ikonky/neutralizer.jpg"; }