// JavaScript Document
function vypocet_splatky(){
    var cena
    var urok
    var doba
    var spodek1
    var spodek2
    var spodek3
    var splatka 
    
    cena = document.forms['formkalk'].uver.value;
    urok = document.forms['formkalk'].urok.value;
    doba = document.forms['formkalk'].delka_uveru.options[document.forms['formkalk'].delka_uveru.options.selectedIndex].value;
    
    doba = (doba * 12) * (-1);
    urok = (urok /100)/12;
        
    spodek1 =(1 + urok);
    spodek2 = Math.pow(spodek1,doba);
    spodek3 = 1 - spodek2;
         
    splatka = Math.round((cena * urok) / spodek3);
    
          
        document.forms['formkalk'].mesicni_splatka.value = splatka;
    }