Button Download With Countdown Timer

HTML

<div style="text-align: center;">


<div id="countdown" class=sec> </div>
<div class="smald">detik</div>
<a id="download" href="http://jsfiddle.net/mazsoma/MLLxT/" rel="nofollow" style="display:none" class=sec>your Link</a>

</div>

CSS

.waitingTimeText{font-size:18px;font-family:Arial,sans-serif;}
.sec{font-size:60px;font-weight:bold;}
.smald{font-size:20px;margin-top:-15px;}

/* CSS Ad block */
#kc56{position:fixed;top:0;left:0;width:100%;height:100%;background-color:#fff;opacity:.98;display:block;z-index:9999;overflow:hidden}
#kc56 p{color:#000;text-align:center;margin:15% auto;font-size:2rem;max-width:750px;display:table;line-height:1.5;}
#kc56 p:before{content:'\f023';font-family:fontawesome;background:#ff675c;color:#fff;text-align:center;display:block;padding:0;width:2em;height:2em;line-height:2em;font-size:2.5rem;clear:both;border-radius:100%;margin:0 auto 3%;font-weight:normal;box-shadow:inset 0 0 5px rgba(0,0,0,.1)}
#kc56 p:hover:before{content:'\f13e'}
#kc56 p a,#kc56 p i{font-size:12px}
#kc56 ~ *{display:none}

JavaScript

window.onload = function() {
    var countdownElement = document.getElementById('countdown'),
        downloadButton = document.getElementById('download'),
        seconds = 10,
        second = 0,
        interval;

    downloadButton.style.display = 'none';

    interval = setInterval(function() {
        countdownElement.firstChild.data = (seconds - second);
        if (second >= seconds) {
            downloadButton.style.display = 'block';
            clearInterval(interval);
        }

        second++;
    }, 1000);
    }
    //]]>