时分秒 定时器

<script type = "text/javascript" >
            var intDiff = parseInt(1800); //倒计时总秒数量
            function timer(intDiff) {
                var f = window.setInterval(function() {
                    var //day = 0,
                        hour = 0 ,
                        minute = 0,
                        second = 0; //时间默认值        
                    if (intDiff > 0) {
                        day = Math.floor(intDiff / (60 * 60 * 24));
                        hour = Math.floor(intDiff / (60 * 60)) - (day * 24);
                        minute = Math.floor(intDiff / 60) - (day * 24 * 60) - (hour * 60);
                        second = Math.floor(intDiff) - (day * 24 * 60 * 60) - (hour * 60 * 60) - (minute * 60);
                    }else{
                        console.log(‘清除定时器了‘)
                        window.clearInterval(f); 
                    }
                    if (minute <= 9) minute = ‘0‘ + minute;
                    if (second <= 9) second = ‘0‘ + second;
                    //$(‘#day_show‘).html(day + "天");
                    $(‘#hour_show‘).html( ‘0‘+hour );
                    $(‘#minute_show‘).html(minute );
                    $(‘#second_show‘).html(second );
                    intDiff--;
                }, 1000);
            }
            $(function() {
                timer(intDiff);
            });
        </script>