javascript 实现RMB转大写

function convertCurrency(currencyDigits) {

// Constants:

    var MAXIMUM_NUMBER = 99999999999.99;

    // Predefine the radix characters and currency symbols for output:

    var CN_ZERO = "零";

    var CN_ONE = "壹";

    var CN_TWO = "贰";

    var CN_THREE = "叁";

    var CN_FOUR = "肆";

    var CN_FIVE = "伍";

    var CN_SIX = "陆";

    var CN_SEVEN = "柒";

    var CN_EIGHT = "捌";

    var CN_NINE = "玖";

    var CN_TEN = "拾";

    var CN_HUNDRED = "佰";

    var CN_THOUSAND = "仟";

    var CN_TEN_THOUSAND = "万";

    var CN_HUNDRED_MILLION = "亿";

    var CN_SYMBOL = "";

    var CN_DOLLAR = "元";

    var CN_TEN_CENT = "角";

    var CN_CENT = "分";

    var CN_INTEGER = "整";

   

// Variables:

    var integral;    // Represent integral part of digit number.

    var decimal;    // Represent decimal part of digit number.

    var outputCharacters;    // The output result.

    var parts;

    var digits, radices, bigRadices, decimals;

    var zeroCount;

    var i, p, d;

    var quotient, modulus;

   

// Validate input string:

    currencyDigits = currencyDigits.toString();

    if (currencyDigits == "") {

        return "不能为空!";

    }

    if (currencyDigits.match(/[^,.\d]/) != null) {

        return "请输入数字!";

    }

    if ((currencyDigits).match(/^((\d{1,3}(,\d{3})*(.((\d{3},)*\d{1,3}))?)|(\d+(.\d+)?))$/) == null) {

        return "请输入正确数字!";

    }

   

// Normalize the format of input digits:

    currencyDigits = currencyDigits.replace(/,/g, "");    // Remove comma delimiters.

    currencyDigits = currencyDigits.replace(/^0+/, "");    // Trim zeros at the beginning.

    // Assert the number is not greater than the maximum number.

    if (Number(currencyDigits) > MAXIMUM_NUMBER) {

        return "超出了最大数字转换!";

    }

   

// Process the coversion from currency digits to characters:

    // Separate integral and decimal parts before processing coversion:

    parts = currencyDigits.split(".");

    if (parts.length > 1) {

        integral = parts[0];

        decimal = parts[1];

        // Cut down redundant decimal digits that are after the second.

        decimal = decimal.substr(0, 2);

    }

    else {

        integral = parts[0];

        decimal = "";

    }

    // Prepare the characters corresponding to the digits:

    digits = new Array(CN_ZERO, CN_ONE, CN_TWO, CN_THREE, CN_FOUR, CN_FIVE, CN_SIX, CN_SEVEN, CN_EIGHT, CN_NINE);

    radices = new Array("", CN_TEN, CN_HUNDRED, CN_THOUSAND);

    bigRadices = new Array("", CN_TEN_THOUSAND, CN_HUNDRED_MILLION);

    decimals = new Array(CN_TEN_CENT, CN_CENT);

    // Start processing:

    outputCharacters = "";

    // Process integral part if it is larger than 0:

    if (Number(integral) > 0) {

        zeroCount = 0;

        for (i = 0; i < integral.length; i++) {

            p = integral.length - i - 1;

            d = integral.substr(i, 1);

            quotient = p / 4;

            modulus = p % 4;

            if (d == "0") {

                zeroCount++;

            }

            else {

                if (zeroCount > 0)

                {

                    outputCharacters += digits[0];

                }

                zeroCount = 0;

                outputCharacters += digits[Number(d)] + radices[modulus];

            }

            if (modulus == 0 && zeroCount < 4) {

                outputCharacters += bigRadices[quotient];

                zeroCount = 0;

            }

        }

        outputCharacters += CN_DOLLAR;

    }

    // Process decimal part if there is:

    if (decimal != "") {

        for (i = 0; i < decimal.length; i++) {

            d = decimal.substr(i, 1);

            if (d != "0") {

                outputCharacters += digits[Number(d)] + decimals[i];

            }

        }

    }

    // Confirm and return the final output string:

    if (outputCharacters == "") {

        outputCharacters = CN_ZERO + CN_DOLLAR;

    }

    if (decimal == "") {

        outputCharacters += CN_INTEGER;

    }

    outputCharacters = CN_SYMBOL + outputCharacters;

    return outputCharacters;

}