Use JS to convert Long data to date type or datetime type __JS

The date format stored in the database is dated (YYYY-MM-DD format date) and datetime (YYYY-MM-DD 00:00:00 format date), when the date data in the database is passed to the front end with a Java program, if the background does not have a method to process the date, The long data is passed to the front end. For example:
Database stored on date: 2017-01-06 20:30:00
The date format for the front-end acquisition (interacting via Ajax) is: 1483705800000
The correct date format should be displayed on the front-end page.
The following is a JS method that converts a long to date or DateTime format:

return YYYY-MM-DD format Date (i):

function Dateformat_1 (longtypedate) {  
    var datetype = "";  
    var date = new Date ();  
    Date.settime (longtypedate);  
    Datetype + + date.getfullyear ();   Year  
    Datetype = "-" + getmonth (date);//month   
    Datetype + = "-" + getday (date);   Daily return  
    datetype;
} 
Returns the month value   
function getmonth (date) {  
    var month = "" of 01-12;  
    month = Date.getmonth () + 1; GetMonth () The resulting month is 0-11  
    if (month<10) {  
        month = "0" + month;  
    }  
    Return month;  
}  
Returns a date of 01-30  
function getday (date) {  
    var day = "";  
    Day = Date.getdate ();  
    if (day<10) {Day  
        = ' 0 ' + day;  
    }  
    return day;  
}

return YYYY-MM-DD format date (ii):

function Dateformat_2 (longtypedate) {  
    var datetype = "";  
    var date = new Date ();  
    Date.settime (longtypedate); 
    Datetype = date.getfullyear () + "-" +getmonth (date) + "-" +getday (date);//yyyy-mm-dd format date return
    Datetype;

return YYYY-MM-DD 00:00:00 format date (i)

function Datetimeformat_1 (longtypedate) {var datetimetype = "";  
    var date = new Date ();  
    Date.settime (longtypedate);   datetimetype+= date.getfullyear (); Year datetimetype+= "-" + getmonth (date);   Month Datetimetype + = "-" + getday (date);   Day datetimetype+= "  " + getHours (date);      When datetimetype+= ":" + getminutes (date);      Minute datetimetype+= ":" + getseconds (date);
Separate return datetimetype;  
    //Returns the month Value function getmonth (date) {var month = "" of 01-12; month = Date.getmonth () + 1;  
    The month getmonth () is 0-11 if (month<10) {month = "0" + month;  
Return month;  
    //Returns a date of 01-30 function getday (date) {var day = "";  
    Day = Date.getdate ();  
    if (day<10) {day = ' 0 ' + day;  
Return day;
    //Returns the Hour function getHours (date) {var hours = "";
    Hours = Date.gethours ();  
    if (hours<10) {hours = "0" + hours;  
   } return hours;
    //Returns the function getminutes (date) {var minute = "";
    minute = Date.getminutes ();  
    if (minute<10) {minute = "0" + minute;  
return minute;
    //Returns the second function getseconds (date) {var second = "";
    Second = Date.getseconds ();  
    if (second<10) {second = "0" + second;  
return second; }

return YYYY-MM-DD 00:00:00 format date (ii)

function Datetimeformat_2 (longtypedate) {  
    var datetimetype = "";  
    var date = new Date ();  
    Date.settime (longtypedate);
    Datetimetype = date.getfullyear () + "-" +getmonth (date) + "-" +getday (date) + " " +gethours (date) + ":" +getminutes (date) + ":" +getseconds (date);//yyyy-mm-dd 00:00:00 format date return
    Datetimetype;

Call Method:
Datetimeformat_1 (1483705800000);
The results obtained are: 2017-01-06 20:30:00