利用Cookie防止刷新的在线考试倒计时JS代码详解编程语言

JavaScript实现的Cookie防止刷新在线考试倒计时

$(function() { 
            var _minute = parseInt("${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; 
                }; 
            }; 
        }