Javascript Number format(n, x)

Number.prototype.format = function (n, x) {
    var re = '\\d(?=(\\d{' + (x || 3) + '})+' + (n > 0 ? '\\.' : '$') + ')';
    return this.toFixed(Math.max(0, ~~n)).replace(new RegExp(re, 'g'), '$&,');
};

'use strict';//from  w ww  .  j a  va  2  s  . co  m

/**
 * Number.prototype.format(n, x)
 *
 * @param integer n: length of decimal
 * @param integer x: length of sections
 */
Number.prototype.format = function (n, x) {
 var re = '\\d(?=(\\d{' + (x || 3) + '})+' + (n > 0 ? '\\.' : '$') + ')';
 return this.toFixed(Math.max(0, ~~n)).replace(new RegExp(re, 'g'), '$&,');
};