人民币大小写转换

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 = "人民币";  
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 == "") {  
//alert("Empty input!");  
return "";  
}  
if (currencyDigits.match(/[^,.\d]/) != null) {  
//alert("Invalid characters in the input string!");  
return "";  
}  
if ((currencyDigits).match(/^((\d{1,3}(,\d{3})*(.((\d{3},)*\d{1,3}))?)|(\d+(.\d+)?))$/) == null) {  
//alert("Illegal format of digit number!");  
return "";  
}  

// 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) {  
alert("您输入的金额太大，请重新输入!");  
return "";  
}  

// 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];  
}  
}  
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;  
}