function ClearForm(form){
form.vstup.value = "";
form.vypocitane.value = "";
}

function checkform(form) {
 if (form.vstup.value==null||form.vstup.value.length==0){
	  alert("\nZadajte sumu");
	  return false;
 }
 return true;
}

// SKK-EUR
function skkeur(form) {
 if (checkform(form)) {
 skk=form.vstup.value;
 skk=skk.replace(',','.');
 eur=(skk/30.126);
 eur=Math.round(eur*100)/100;
 form.vypocitane.value=eur+' €';
 }
 return;
}

// EUR-SKK
function eurskk(form) {
 if (checkform(form)) {
 eur=form.vstup.value;
 eur=eur.replace(',','.');
 skk=(eur*30.126);
 skk=Math.round(skk*100)/100;
 form.vypocitane.value=skk+' Sk';
 }
 return;
}