how to add a random interval to this countdown
<p>I have the following code. It's a countdown timer and I have to input the start time for the counter. I am wondering how can I make it place a random interval between 30 seconds to 2 minutes for the <code>defaultTimer</code> variable.</p>

<pre><code>$(function() {
    var defaultTimer = 25, // Default amount of seconds if url variable is not found
        callback = function() {
            // Will be executed when the timer finishes
            alert("Time!!");   
        };

    var counter = 1, timer, 
        match = document.location.href.match(/[\?|&amp;]timer=(\d+)/i),
        totalTime = match ? match[1] : defaultTimer;

    timer = setInterval(function() {
        if (totalTime != -1 &amp;&amp; !isNaN(totalTime)) {
            val = 'Time left: ' + (function() {
                var m = Math.floor(totalTime / 60);
                if (m &lt; 10) {
                    return '0'.concat(m);
                } else {
                    return m;
                }
            })() + ':' + (function() {
                var s = totalTime % 60;
                if (s &lt; 10) {
                    return '0'.concat(s);
                } else {
                    return s;
                }
            })();

            $('#counter').html(val);
            totalTime--;
        } else {
            window.clearInterval(timer);
            timer = null;
            callback();
        }
    }, 1000);
});
</code></pre>
