What is the JS equivalent to the PHP function number_format?

The same equivalent of number_format in js can found here

function number_format (number, decimals, dec_point, thousands_sep) {
    // Strip all characters but numerical ones.
    number = (number + '').replace(/[^0-9+\-Ee.]/g, '');
    var n = !isFinite(+number) ? 0 : +number,
        prec = !isFinite(+decimals) ? 0 : Math.abs(decimals),
        sep = (typeof thousands_sep === 'undefined') ? ',' : thousands_sep,
        dec = (typeof dec_point === 'undefined') ? '.' : dec_point,
        s = '',
        toFixedFix = function (n, prec) {
            var k = Math.pow(10, prec);
            return '' + Math.round(n * k) / k;
        };
    // Fix for IE parseFloat(0.55).toFixed(0) = 0;
    s = (prec ? toFixedFix(n, prec) : '' + Math.round(n)).split('.');
    if (s[0].length > 3) {
        s[0] = s[0].replace(/\B(?=(?:\d{3})+(?!\d))/g, sep);
    }
    if ((s[1] || '').length < prec) {
        s[1] = s[1] || '';
        s[1] += new Array(prec - s[1].length + 1).join('0');
    }
    return s.join(dec);
}

Just use toLocaleString on an integer object.

https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Number/toLocaleString#Browser_compatibility

let x = 1234567;
//if x is a string/non-number, use parseInt/parseFloat to convert to a number. Thanks @Aleksandr Kopelevich
x.toLocaleString('us', {minimumFractionDigits: 2, maximumFractionDigits: 2})

is this what you'd like to get?

yourFloatVarHere.toFixed(2);

voilà.

Native "Intl" object approach:

var amount = 5000.25;
var locale = 'de';
var options = {style: 'currency', currency: 'eur', minimumFractionDigits: 2, maximumFractionDigits: 2};
var formatter = new Intl.NumberFormat(locale, options);

console.log(formatter.format(amount));

http://jsfiddle.net/arturrelax/sa9jL138/1/

More information at: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl