时间倒计时-时-分-秒

var time_end = new Date();  // 设定结束时间
time_end = time_end.getTime()+7200000;//设置时间间隔为2小时
setTimeout("show_time()",1000);
function show_time() {
    var time_start = new Date();//获得当前时间
    time_start.getTime();
    var time_distance = time_end-time_start;
    var int_hour, int_minute, int_second;
    if(time_distance>=0){
        int_hour =  Math.floor(time_distance/3600000);//取小时
        time_distance -= int_hour * 3600000;
        int_minute = Math.floor(time_distance/60000);//取分钟
        time_distance -= int_minute * 60000;
        int_second = Math.floor(time_distance/1000);//取秒钟

        // 时分秒为单数时、前面加零站位
        if(int_hour < 10)
            int_hour = "0" + int_hour;
        if(int_minute < 10)
            int_minute = "0" + int_minute;
        if(int_second < 10)
            int_second = "0" + int_second;
        // 显示时间
        $("#time_h").text(int_hour);
        $("#time_m").text(int_minute);
        $("#time_s").text(int_second);
        setTimeout("show_time()",1000);
    }
}