datetimeparse (timestamp, format, prefix){

//转换时区

let currentZoneTime =new Date(timestamp);

let currentTimestamp=currentZoneTime.getTime();

let offsetZone =currentZoneTime.getTimezoneOffset() /60;     //如果offsetZone>0是西区，西区晚

    let offset=null;

  //客户端时间与服务器时间保持一致，固定北京时间东八区。

    offset=offsetZone +8;

currentTimestamp=currentTimestamp+offset*3600*1000

let newtimestamp=null;

if(currentTimestamp){

if(currentTimestamp.toString().length ===13){

newtimestamp=currentTimestamp.toString()

}else if(currentTimestamp.toString().length ===10){

newtimestamp=currentTimestamp +'000'

        }else{

                 newtimestamp=null

        }

}else{

         newtimestamp=null

    };

let dateobj =newtimestamp ?new Date(parseInt(newtimestamp)) :new Date()

let YYYY =dateobj.getFullYear()

let MM =dateobj.getMonth() >8 ?dateobj.getMonth() +1 :'0' + (dateobj.getMonth() +1)

let DD =dateobj.getDate() >9 ?dateobj.getDate() :'0' +dateobj.getDate()

let HH =dateobj.getHours() >9 ?dateobj.getHours() :'0' +dateobj.getHours()

let mm =dateobj.getMinutes() >9 ?dateobj.getMinutes() :'0' +dateobj.getMinutes()

let ss =dateobj.getSeconds()>9?dateobj.getSeconds():'0'+dateobj.getSeconds()

let output ='';

let separator ='/'

    if (format) {

separator = format.match(/-/) ?'-' :'/'

        output += format.match(/yy/i) ?YYYY :''

        output += format.match(/MM/) ? (output.length ?separator :'') +MM :''

        output += format.match(/dd/i) ? (output.length ?separator :'') +DD :''

        output += format.match(/hh/i) ? (output.length ?' ' :'') +HH :''

        output += format.match(/mm/) ? (output.length ?':' :'') +mm :''

        output += format.match(/ss/i) ? (output.length ?':' :'') +ss :''

    }else {

output +=YYYY +separator +MM +separator +DD

    }

output = prefix ? (prefix +output) :output

    return newtimestamp ?output :''

},