基于jQuery+Cookie实现的防止刷新的在线考试倒计时

$(function() {
      var _minute = parseInt("${exampaper.paperTime }");
      var _expiresHours = _minute * 60 * 1000;
        
      if(!hasSetCookie()){
        addCookie("${examinee.examineeId}", _expiresHours, _expiresHours);
      } 
      settime($("#remainTime")); 
    });
    function hasSetCookie(){
      var strCookie = document.cookie;
      var arrCookie = strCookie.split("; ");
      for (var i = 0; i < arrCookie.length; i++) {
        var arr = arrCookie[i].split("=");
        if (arr[0] == "${examinee.examineeId}") {
          return true;
        }
      };
      return false;
    }
    //开始倒计时
    function settime(remainTime) {
      var _time = getCookieValue("871d31bacfd4451484c5f70f8860c2a9");
      var _countdown = parseInt(getCookieValue("${examinee.examineeId}")) / 1000;
       
      if (_countdown <= 0) {
        alert("考试时间到！");
        endExam();
      } else {
        var _second = _countdown % 60;
        var _minute = parseInt(_countdown / 60) % 60;
        var _hour = parseInt(parseInt(_countdown / 60) / 60);
 
        if (_hour < 10)
          _hour = "0" + _hour.toString();
        if (_second < 10)
          _second = "0" + _second.toString();
        if (_minute < 10)
          _minute = "0" + _minute.toString();
 
        remainTime.html(_hour + ":" + _minute + ":" + _second);
        _countdown--;
        editCookie("${examinee.examineeId}", _countdown * 1000, _countdown * 1000);
      }
      //每1000毫秒执行一次
      setTimeout(function() {
        settime(remainTime);
      }, 1000);
    };
 
    //时添加cookie
    function addCookie(name, value, expiresHours) {
      var cookieString = name + "=" + escape(value); //escape() 函数可对字符串进行编码，这样就可以在所有的计算机上读取该字符串。
      //判断是否设置过期时间,0代表关闭浏览器时失效
      if (expiresHours > 0) {
        var date = new Date();
        date.setTime(date.getTime() + expiresHours * 1000);
        cookieString = cookieString + ";expires=" + date.toUTCString();
      }
      document.cookie = cookieString;
    }
 
    //修改cookie的值
    function editCookie(name, value, expiresHours) {
      var cookieString = name + "=" + escape(value);
      if (expiresHours > 0) {
        var date = new Date();
        date.setTime(date.getTime() + expiresHours * 1000); //单位是毫秒
        cookieString = cookieString + ";expires=" + date.toGMTString();
      }
      document.cookie = cookieString;
    }
 
    //根据名字获取cookie的值
    function getCookieValue(name) {
      var strCookie = document.cookie;
      var arrCookie = strCookie.split("; ");
      for (var i = 0; i < arrCookie.length; i++) {
        var arr = arrCookie[i].split("=");
        if (arr[0] == name) {
          return unescape(arr[1]);
          break;
        } else {
          continue;
        };
      };
    }