I Need modify countdown in jQuery

Question

I want to modify my jQuery code please help. this is countdown timer start from 30 and end on 0 and then its stop.

I want when my countdown on 0 then its start again from 30. I want randomly countdown from 30 to 0 and then start 30 to 0.

// Random Countdown Timer Script, by http://ctrtard.com

var timer;

function startCount() {
    timer = setInterval(count, 1000); // 200 = 200ms delay between counter changes. Lower num = faster, Bigger = slower.
}

function count() {
    var rand_no = Math.ceil(1 * Math.random()); // 9 = random decrement amount. Counter will decrease anywhere from 1 - 9.
    var el = document.getElementById('counter');
    var currentNumber = parseFloat(el.innerHTML);
    var newNumber = currentNumber - rand_no;
    if (newNumber > 0) {
        el.innerHTML = newNumber;
    } else {
        el.innerHTML = "Sold Out"; // This message is displayed when the counter reaches zero.
    }
}

Answer 1

function count() {
    var rand_no = Math.ceil(1 * Math.random()); // 9 = random decrement amount. Counter will decrease anywhere from 1 - 9.
    var el = document.getElementById('counter');
    var currentNumber = parseFloat(el.innerHTML);
    var newNumber = currentNumber - rand_no;
    if (newNumber > 0) {
        el.innerHTML = newNumber;
    } else {
        setElemVal(el , 30);
        count();   
    }
}

function setElemVal(el , val) {
    el.innerHTML = '';
    el.innerHTML = val;
}

Just add another function to reset the value and change the else condition.

FIDDLE HERE