js时间加减与时间对象与字符串之间的转换

//js时间的加法   function timeAdd(){   //7天的毫秒数   加7天var interval = 7*24*60*60*1000;   var now = new Date();  now.setTime(now.getTime()+interval);   }     //将js的时间对象转换为字符串yyyyMMddHHssmm   function jsTimeToString(time){   var year=time.getYear();   var month=time.getMonth()+1;   var day=time.getDate();   var hour=time.getHours();   var minute=time.getMinutes();   var second=time.getSeconds();   if(month<10){       month="0"+month;   }   if(day<10){       day="0"+day;   }   if(hour<10){       hour="0"+hour;   }   if(minute<10){       minute="0"+minute;   }   if(second<10){       second="0"+second;   }   var strTime = year+""+month+""+day+""+hour+""+minute+""+second;    return strTime;   }      //将字符串转换为js的时间对象，  字符串格式yyyyMMddHHssmm   function stringToJsTime(time) {   var y = time.substring(0,4);   var m = time.substring(4,6)-1;   var d = time.substring(6,8);   var h = time.substring(8,10);   var mm = time.substring(10,12);   var ss = time.substring(12,14);   var date = new Date(y,m,d,h,mm,ss,0);   return date;   } //将字符串转换为js的时间对象，  字符串格式yyyy-MM-dd HH:ss:mm     function stringToJsTime_(timeString) {    var y = timeString.substring(0,4);    var m = timeString.substring(5,7)-1;    var d = timeString.substring(8,10);    var h = timeString.substring(11,13);    var mm = timeString.substring(14,16);    var ss = timeString.substring(17,19);    var time = new Date(y,m,d,h,mm,ss,0);    return time;    }