Javascript Locale Currency format

localeNumberFormat.js

 function localeNumberFormat(amount, currencySymbol, delimiter, decimalPlaces) {
        // setup some default values
        if (typeof decimalPlaces === 'undefined' || decimalPlaces === null) {
            decimalPlaces = 0;
        }
         if (typeof decimalPlaces === 'undefined' || delimiter === null) { delimiter = ','; }

        //check that the value can be recognised as an Floating point number
        try {
            amount = parseFloat(amount);
            amount = amount.toFixed(decimalPlaces);
        }
        catch (e) {
            return 'NaN';
        }

        // setup some variables for delimiting the strings with commas
        var isNegative = amount.indexOf('-') >= 0 ? '-' : '';
        amount = amount.replace('-', '');

        var amtLen = amount.length;
        var decPoint = amount.indexOf('.');
        var wholeNumberEnd = decPoint > 0 ? amtLen - (amtLen - decPoint) : amtLen;

        var wholeNumber = amount.substr(0, wholeNumberEnd);
        var decimal = amount.substr(wholeNumberEnd, amtLen - wholeNumberEnd);

        var rvsNumber = wholeNumber.split('').reverse().join('');
        var output = '';

        for (i = 0; i < wholeNumberEnd; i++) {
            if (i % 3 == 0 && i != 0 && i != wholeNumberEnd) { output += ','; }
            output += rvsNumber.charAt(i);
        }

        output = isNegative + currencySymbol + output.split('').reverse().join('') + decimal;

        return output;
    }