简易倒计时

function countdown() {
        var oCountdown = $('.countdown');
        var sTime = oCountdown.attr('data-time');
        if (!sTime) return;
        var endTime = new Date(sTime);
        var nowTime = new Date();
        var disTimer = endTime - nowTime;
        if (disTimer <= 0) return;
        oCountdown.show();
        var ctTimer = null;
        var speed = 1000;
        var aItem = oCountdown.find('.time-item');

        ctTimer = setInterval(function() {
            disTimer -= speed;
            if (disTimer <= 0) {
                clearInterval(ctTimer);
            } else {
                var data = formatTimer(disTimer);
                aItem.eq(0).html(data.h);
                aItem.eq(1).html(data.m);
                aItem.eq(2).html(data.s);
            }

        }, speed);
    }

    function formatTimer(timer) {
        var hours = parseInt((timer % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60));
        var minutes = parseInt((timer % (1000 * 60 * 60)) / (1000 * 60));
        var seconds = parseInt((timer % (1000 * 60)) / 1000);
        return {
            h: hours > 10 ? hours : '0' + hours,
            m: minutes > 10 ? minutes : '0' + minutes,
            s: seconds > 10 ? seconds : '0' + seconds
        };
    }