function validate()
{
    if (!isNaturalNumber(document.asset.n, " for the Number of years to Purchase."))
    {
        return false;
    }

    if (!isNaturalNumber(document.asset.cp, " for the Current Price."))
    {
        return false;
    }

    if (!isValueInRange(document.asset.pi, 1, 100, " for the Inflation rate."))
    {
        return false;
    }

    if (!isNaturalNumber(document.asset.cs, " for the Current Savings."))
    {
        return false;
    }

    if (!isValueInRange(document.asset.sr, 1, 100, " for the Rate of return on Savings."))
    {
        return false;
    }

	return true;
}


function calc()
{
    var n = parseFloat(document.asset.n.value);
    var cp = parseFloat(document.asset.cp.value);
    var pi = parseFloat(document.asset.pi.value / 100);
    var cs = parseFloat(document.asset.cs.value);
    var sr = parseFloat(document.asset.sr.value / 100);
    var ec = parseFloat(cp * (Math.pow((1 + pi), n)));
    var ts = parseFloat(cs * (Math.pow((1 + sr), n)));
    var es = parseFloat(ec - ts);
    if (es < 0)
    {
        es = 0;
    }

    document.asset.ec.value = round(ec, 2);
    document.asset.ts.value = round(ts, 2);
    document.asset.es.value = round(es, 2);
}

function clean()
{
    document.asset.n.value = "";
    document.asset.cp.value = "";
    document.asset.pi.value = "";
    document.asset.cs.value = "";
    document.asset.sr.value = "";
    document.asset.ec.value = "";
    document.asset.ts.value = "";
    document.asset.es.value = "";
}