jQuery - totalling up the value of several numeric <select> elements?

I have a form that asks for addresses. After each address, we ask how long the person has lived in that address, with <select> dropdowns for Years and Months.

I have a jQuery event each time the <select> is changed:

var prev_addresses = 0;
$('select.months, select.years').change(function() {

    // Calculate total months
    var months = $('select.months').val();
    var years = $('select.years').val();
    var total_months = parseInt(months) + parseInt(years*12);   // We parseInt() to avoid concatenation

    console.log('Total months: '+total_months);

    if(total_months < 12) {
        // Find the next div.hidden-address
        prev_addresses = prev_addresses+1;
        console.log('Number of previous addresses: '+prev_addresses);
        console.log('');
        $('div.hidden-address').clone(true).appendTo('#previous-addresses').slideToggle();
    }
});

I want this to keep on happening all the while a person has less than 12 months of addresses. However after the first time the event fires, every time a <select> is updated the console just logs the first set of values (开发者_如何学Gofrom the original Year and Month selects, even though there are now multiple ones).

I want to total up the values of every <select> element on a page, even after more are added dynamically. How can I do this?

Hope that makes sense, I'm happy to clarify if you need further details.

Thanks,

Jack

---

Loop through all select boxes, and add the value to a variable, something like this:

var totalMonths = 0;
$('select.months').each(function () {
    totalMonths += $(this).val();
});

$('select.years').each(function () {
    totalMonths += 12 * $(this).val();
});