Javascript Mining Calc

<script type="text/javascript">
function formatSeconds(output) {
    var seconds = 0;
    var minutes = 0;
    var hours = 0;
    var days = 0;
    var weeks = 0;
    var years = 0;

    while (milliseconds >= 1000) {
        milliseconds -= 1000;
        seconds += 1;
    }

    while (seconds >= 60) {
        seconds -= 60;
        minutes += 1;
    }

    while (minutes >= 60) {
        minutes -= 60;
        hours += 1;
    }

    while (hours >= 24) {
        hours -=24;
        days += 1;
    }

    while (days >= 7) {
        days -= 7;
        weeks += 1;
    }

    while (weeks >= 52) {
        weeks -= 52;
        years += 1;
    }

    return [years, weeks, days, hours, minutes, seconds, milliseconds];
}

function printFormat(array) {
    if (array[0] !== 0) {
        console.log(array[0] + " Years,");
    }
    if (array[1] !== 0) {
        console.log(array[1] + " Weeks,");
    }
    if (array[2] !== 0) {
        console.log(array[2] + " Days,");
    }
    if (array[3] !== 0) {
        console.log(array[3] + " Hours,");
    }
    if (array[4] !== 0) {
        console.log(array[4] + " Minutes,");
    }
    if (array[5] !== 0) {
        console.log(array[5] + " Seconds");
    }
    if (array[6] !== 0) {
        console.log(array[6] + " Milliseconds");
    }
    return;
}

var seconds = prompt("How many seconds does it take you to complete one cycle? Please use all decimals if you want more accuracy.");
var cycle =  prompt("How much do you get per cycle? Please use all decimals if you want more accuracy.");
var lasers = prompt("How many strip miners or mining lasers are you using?");
var storage = prompt("How large is the container you are trying to fill? No need to type m3 or cubic meters.");

var output = (seconds / (cycle * lasers)) * storage;
//var output = (120 / (2000 * 3)) * 50000; = 1000?

console.log(output);

printFormat(formatSeconds(output));
</script>