你可以使用toISOString函数:

var today = new Date();
today.toISOString().substring(0, 10);

它会给你一个“yyyy-mm-dd”格式。

<pre>Date.prototype.getFromFormat = function(format) {
    var yyyy = this.getFullYear().toString();
    format = format.replace(/yyyy/g, yyyy)
    var mm = (this.getMonth()+1).toString(); 
    format = format.replace(/mm/g, (mm[1]?mm:"0"+mm[0]));
    var dd  = this.getDate().toString();
    format = format.replace(/dd/g, (dd[1]?dd:"0"+dd[0]));
    var hh = this.getHours().toString();
    format = format.replace(/hh/g, (hh[1]?hh:"0"+hh[0]));
    var ii = this.getMinutes().toString();
    format = format.replace(/ii/g, (ii[1]?ii:"0"+ii[0]));
    var ss  = this.getSeconds().toString();
    format = format.replace(/ss/g, (ss[1]?ss:"0"+ss[0]));
    var ampm = (hh >= 12) ? "PM" : "AM";
    format = format.replace(/ampm/g, (ampm[1]?ampm:"0"+ampm[0]));
    return format;
};
var time_var = $('#899_TIME');
var myVar = setInterval(myTimer, 1000);
function myTimer() {
    var d = new Date(); 
    var date = d.getFromFormat('dd-mm-yyyy hh:ii:ss:ampm');
    time_var.text(date);

} </pre>

use the code and get the output like **26-07-2017 12:29:34:PM**

check the below link for your reference

https://parthiban037.wordpress.com/2017/07/26/date-and-time-format-in-oracle-apex-using-javascript/ 

Try this:

函数showdate () {

var a = new Date();
var b = a.getFullYear();
var c = a.getMonth();
(++c < 10)? c = "0" + c : c;
var d = a.getDate();
(d < 10)? d = "0" + d : d;
var final = b + "-" + c + "-" + d; 

return final;


} 

document.getElementById("todays_date").innerHTML = showdate();

yyyymmdd=x=>（f=x=>（x<10&&'0'）+x，x.getFullYear（）+f（x.getMonth（）+1）+f（x.getDate（）））; 警报（年年月日（新日期））;

日期短代码拯救!

const dateShortcode = require('date-shortcode')
dateShortcode.parse('{YYYYMMDD}', new Date())
//=> '20180304'

使用padStart:

Date.prototype.yyyymmdd = function() {
    return [
        this.getFullYear(),
        (this.getMonth()+1).toString().padStart(2, '0'), // getMonth() is zero-based
        this.getDate().toString().padStart(2, '0')
    ].join('-');
};