js获取当前系统时间 && js获取当前系统时间-24小时 && 当前系统时间+24小时

      /**
* 获取当前时间
* @returns {String}
*/
function getNowFormatDate() {
   var date = new Date();
   var seperator1 = "-";
   var seperator2 = ":";
   var month = date.getMonth() + 1;
   var hours = date.getHours();
   var minutes = date.getMinutes();
   var strDate = date.getDate();
   var seconds = date.getSeconds();
   if (month >= 1 && month <= 9) {
       month = "0" + month;
   }
   if (strDate >= 0 && strDate <= 9) {
       strDate = "0" + strDate;
   }
   if(hours>=0 && hours<=9){
    hours = "0"+hours;
   }
   if(minutes>=0 && minutes<=9){
    minutes = "0"+minutes;
   }
   if(seconds>=0 && seconds<=9){
    seconds = "0"+seconds;
   }
   var currentdate = date.getFullYear() + seperator1 + month + seperator1 + strDate
           + " " + hours + seperator2 + minutes
           + seperator2 + seconds;
   return currentdate;
}

/**
* 获取当前时间前一天
* @returns {String}
*/
function getNowAgoFormatDate() {
   var date = new Date();
   var seperator1 = "-";
   var seperator2 = ":";
   var month = date.getMonth() + 1;
   var hours = date.getHours()-24;
   var minutes = date.getMinutes();
   var strDate = date.getDate();
   var seconds = date.getSeconds();
   if (month >= 1 && month <= 9) {
       month = "0" + month;
   }
   if (strDate >= 0 && strDate <= 9) {
       strDate = "0" + strDate;
   }
   if(hours>=0 && hours<=9){
    hours = "0"+hours;
   }
   if(minutes>=0 && minutes<=9){
    minutes = "0"+minutes;
   }
   if(seconds>=0 && seconds<=9){
    seconds = "0"+seconds;
   }
   var currentdate = date.getFullYear() + seperator1 + month + seperator1 + strDate
           + " " + hours + seperator2 + minutes
           + seperator2 + seconds;
   return currentdate;
}

 //获取当前时间+24小时
function GetDateStr(bngDate) {
    var date =bngDate;
   var seperator1 = "-";
   var seperator2 = ":";
   var month = date.getMonth() + 1;
   var hours = date.getHours();
   var minutes = date.getMinutes();
   var strDate = date.getDate()+1;
   var seconds = date.getSeconds();
   if (month >= 1 && month <= 9) {
       month = "0" + month;
   }
   if (strDate >= 0 && strDate <= 9) {
       strDate = "0" + strDate;
   }
   if(hours>=0 && hours<=9){
    hours = "0"+hours;
   }
   if(minutes>=0 && minutes<=9){
    minutes = "0"+minutes;
   }
   if(seconds>=0 && seconds<=9){
    seconds = "0"+seconds;
   }
   var currentdate = date.getFullYear() + seperator1 + month + seperator1 + strDate
           + " " + hours + seperator2 + minutes
           + seperator2 + seconds;
   return currentdate;
}        

                                                                                                                                                                                                                                                              
                        --                                                                                                                --- yt.Liu