How to format date in JavaScript?

To put the current date in the dd/mm/yyyy format, you can use a function to do this, in order to simplify your work:

unction currentformateddata(){
    var date = new Date(),
        day  = data.getDate().toString(),
        dayF = (day.length == 1) ? '0'+day : day,
        month  = (data.getMonth()+1).toString(), //+1 cause in getMonth January starts at zero.
        monthF = (month.length == 1) ? '0'+month : month,
        yearF = data.getFullYear();
    return dayF+"/"+monthF+"/"+yearF;
}

For dd/mm/yyyy

Example

Today (result of the code above) in a <input type=text id=Data>

$('#Data').val(currentformateddata);

It would result the following in the input value:

19/02/2022

Update: in ES8 (ECMAScript 2017) the padStart method was implemented, so the solution can be used in a simpler way:

function dataAtualFormatada(){
    var date = new Date(),
        day  = data.getDate().toString().padStart(2, '0'),
        month  = (data.getMonth()+1).toString().padStart(2, '0'), //+1 cause in getMonth January starts at zero.
        year  = data.getFullYear();
    return day+"/"+month+"/"+year;
}

Observation

This last solution will not work in Internet Explorer and in browsers that do not support ES8, for more information see the compatibility table.

Polyfill

// https://github.com/uxitten/polyfill/blob/master/string.polyfill.js
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/padStart
if (!String.prototype.padStart) {
    String.prototype.padStart = function padStart(targetLength, padString) {
        targetLength = targetLength >> 0; //truncate if number, or convert non-number to 0;
        padString = String(typeof padString !== 'undefined' ? padString : ' ');
        if (this.length >= targetLength) {
            return String(this);
        } else {
            targetLength = targetLength - this.length;
            if (targetLength > padString.length) {
                padString += padString.repeat(targetLength / padString.length); //append to original to ensure we are longer than needed
            }
            return padString.slice(0, targetLength) + String(this);
        }
    };
}

Reference:

https://pt.stackoverflow.com/questions/6526/como-formatar-data-no-javascript