function pmt(interest, months, principal) {
        base = interest + 1;
        t = Math.pow(base, months);
        result = principal * t * interest / (t - 1);
        return result;
}

function getMonthlyRate(totalPrice, yearInterest, months) {
    TAX = 1.08;
    capital = (totalPrice * TAX) / months;    
    sumaFinantata = totalPrice * TAX;
    interest = yearInterest / 12;

    principal = sumaFinantata;
    pmtValue = pmt(interest, months, principal);        
    monthlyInterest = ((pmtValue * months) - totalPrice * TAX) / months;
        rataLunara = capital + monthlyInterest;

    return Math.round(rataLunara * 100) / 100;
}

function displayRates(totalPriceRon, euro) {
    ronYearInterest = 0.2555;
    euroYearInterest = 0.18225;
    months = new Array(12, 18, 24, 36, 48, 60);
    for (i=0; i < months.length; i++) {        
        rateRon = getMonthlyRate(totalPriceRon, ronYearInterest, months[i]);
        rateEuro = getMonthlyRate(totalPriceRon / euro, euroYearInterest, months[i]);
        document.getElementById('ron' + months[i]).innerHTML = rateRon;
        document.getElementById('eur' + months[i]).innerHTML = rateEuro;
    }    
}

function displayRONRate(price, months, element) {
       var rate=0; 
    ronYearInterest = 0.2555;
        rate = getMonthlyRate(price, ronYearInterest, months);
    document.getElementById(element).innerHTML = rate;
}

function displayEURORate(price, months, euro) {
        euroYearInterest = 0.18225;
        rate = getMonthlyRate(price / euro, euroYearInterest, months);
    document.getElementById('euro-rate').innerHTML = rate;
}

function isDigit(num) {
    if (num.length > 1) {
        return false;
    }

    var string="1234567890";
    if (string.indexOf(num) != -1) {
        return true;
    }

    return false;
}

function isBlank(val){
    if(val==null){return true;}
    for(var i=0;i<val.length;i++) {
        if ((val.charAt(i)!=' ')&&(val.charAt(i)!="\t")&&(val.charAt(i)!="\n")&&(val.charAt(i)!="\r")){return false;}
        }
    return true;
}

function isInteger(val){
    if (isBlank(val)) {
        return false;
    }
    
    for(var i = 0; i < val.length; i++){
        if(!isDigit(val.charAt(i))) { 
            return false;
        }
    }
    return true;
}

function displayCnRate(totalPrice, months) {
    if (!isInteger(totalPrice)) {
        alert("Valoare introdusa in campul \"Valoare credit\" trebuie sa fie un numar intreg.");
    }

    TAX = 1.06;
    yearInterest = 0.33;
    capital = (totalPrice * TAX) / months;    
    sumaFinantata = totalPrice * TAX;
    interest = yearInterest / 12;

    principal = sumaFinantata;
    pmtValue = pmt(interest, months, principal);    
    monthlyInterest = ((pmtValue * months) - totalPrice * TAX) / months;
        rataLunara = capital + monthlyInterest;

    document.getElementById("rate").innerHTML = Math.round(rataLunara * 100) / 100 + ' RON';
}