@font-face{

            font-family: "Digital-7 Mono";

            src: url('Digital-7Mono.TTF');

        }

        div{

            width: 500px;

        }

       .contain{

            text-align: right;

            font-size: 18px;

            margin-top: 10px;

            margin-bottom: 10px;

        }

        .contain span{

            font-family: "Digital-7 Mono";

            font-size: 36px;

            color: #555;

            padding-left: 10px;

        }       

<div class="contain"></div>

<script src="jquery.min.js"></script>

<script type="text/javascript">

    var displayMode = 1;

    var time;

    $(".contain").click(function(){

        displayMode *= -1;

        Time(time, displayMode);

    });

    // 返回不同月份不同天数的方法

    function getDaysInMonth(month) {

        var data = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];

        return data[month];

    }

    // 设置开始时间

    function start(year,month,day,hour,min,sec,mill){

        var starttime =new Date();

        starttime.setFullYear(year,month-1,day);

        starttime.setHours(hour,min,sec,mill);

        time =starttime;

        return time;

    }

    start(2015,2,20,21,0,0,0);

    function Time(date,mode){

        var years = NaN;

        var months = NaN;

        var current =new Date();

        var seconds =(Date.parse(current) - Date.parse(date)) /1000; //获取时间差的秒数

        var days =Math.floor(seconds / (3600 * 24)); //总天数

        seconds = seconds % (3600 * 24);  //总秒数 % 一天的秒数 下面的同理

        var hours =Math.floor(seconds / 3600); 

        seconds = seconds % 3600;

        var minutes = Math.floor(seconds / 60);

        seconds = seconds % 60;

        // 判断假如时分秒小时10的话 前面加0

        (seconds <10)? seconds ="0"+seconds:seconds=seconds;

        (hours <10)? hours ="0"+hours:hours=hours;

        (minutes <10)? minutes ="0"+minutes:minutes=minutes;

        if (mode == 1) {

            days = current.getDate() - date.getDate(); //当前日 - 开始日

            if (days < 0) {

                days += getDaysInMonth(current.getMonth());

                current.setDate(current.getDate() -1);

            }

            months = current.getMonth() - date.getMonth();

            if (months < 0) {

                months += 12;

                current.setFullYear(current.getFullYear() - 1);

            }

            years = current.getFullYear() - date.getFullYear();

        } else {

            days = Math.floor((current.getTime() - date.getTime()) / (1000 * 3600 * 24));

        }

        var result = (years > 0 ? "<span class='years'>" + years + "</span> year ":"")

            result += (months >= 0 ? "<span class='months'>" + months + "</span> month ":"");

            result += "<span class='days'>" + days + "</span> day ";

            result += "<span class='hours'>" + hours + "</span> hr "

            result += "<span class='minutes'>" + minutes + "</span> min "

            result += "<span class='seconds'>" + seconds + "</span> sec"

        $(".contain").html(result);

    }

    Time(time,displayMode);

    setInterval(function(){

        Time(time,displayMode);

    },1000)

</script>