时间戳倒计时

var nowtime = new Date(),  //获取当前时间
                    endtime = new Date("2020/8/8");  //定义结束时间
    
                var lefttime = endtime.getTime() - nowtime.getTime(),  //距离结束时间的毫秒数
                    leftd = Math.floor(lefttime/(1000*60*60*24)),  //计算天数
                    lefth = Math.floor(lefttime/(1000*60*60)%24),  //计算小时数
                    leftm = Math.floor(lefttime/(1000*60)%60),  //计算分钟数
                    lefts = Math.floor(lefttime/1000%60);  //计算秒数
    
                this.countdown =  leftd + "天" + lefth + ":" + leftm + ":" + lefts;  //返回倒计时的字符串
                                
                                this.day =  leftd;//返回天 
                this.time = lefth;//返回时
                this.minute = leftm;//返回分
                this.second = lefts;//返回秒
                
                console.log(this.time)