date get dd-mm-yyyy and format change to yyyy-mm-dd in javascript code example

Example 1: javascript date today dd mm yyyy

var today = new Date();
var dd = String(today.getDate()).padStart(2, '0');
var mm = String(today.getMonth() + 1).padStart(2, '0'); //January is 0!
var yyyy = today.getFullYear();

today = mm + '/' + dd + '/' + yyyy;
document.write(today);

Example 2: javascript format date yyyy-mm-dd

let today = new Date()
today.toISOString().split('T')[0]