I hope this is what you're looking for:
const today = new Date();
const yyyy = today.getFullYear();
let mm = today.getMonth() + 1; // Months start at 0!
let dd = today.getDate();
if (dd < 10) dd = '0' + dd;
if (mm < 10) mm = '0' + mm;
const formattedToday = dd + '/' + mm + '/' + yyyy;
document.getElementById('DATE').value = formattedToday;