转化为大写金额JavaScript

function num2CNY(num) {
    var intArr = [], decimalArr = [];//分别保存整数部分和小数部分的拆分结果
    var resInt = "", resDecimal = "";//保存最终结果
    var Unit = ["", "万", "亿"];//单位数组，用于转换
    var CN_NUM = ["零","壹","贰","叁","肆","伍","陆","柒","捌","玖"];//数字对应的中文

    //将数据按照每四位一组进行拆分，保存到intArr中
    num = Math.abs(num).toFixed(2);
    var integer = Math.floor(num).toString().split("").reverse().join("");
    var len = integer.length;
    for (var i = 0; i < len; i += 4) {
        intArr.push(integer.substr(i, 4).split("").reverse().join(""));
    }

    //对整数部分进行转换
    for (var i = 0, unitNum = Unit.length; i < unitNum; i++) {
        var group = intArr[i] ? intArr[i] : "";
        var res = "", zeroFlag = 0;
        for (var j = 0, groupLen = group.length; j < groupLen; j++) {
            var num = parseInt(group.charAt(j));
            if (num !== 0) {
                res += CN_NUM[num] + ["", "拾", "佰", "仟"][j];
                zeroFlag = 0;
            } else if (zeroFlag !== j) {
                res += "零";
                zeroFlag = j;
            }
        }
        resInt = res + (res !== "" ? Unit[i] : "") + resInt;
    }

    //对小数部分进行转换
    var decimal = num.split(".")[1];
    for (var i = 0, decimalLen = decimal.length; i < decimalLen; i++) {
        var num = parseInt(decimal.charAt(i));
        resDecimal += num !== 0 ? CN_NUM[num] + ["角", "分"][i] : "";
    }

    //对结果进行特殊处理，消除多余的“零”
    var res = resInt + (resInt !== "" ? "元" : "") + resDecimal;
    res = res.replace(/零{2,}/g, "零").replace(/(零+)(元)/g, "$2").replace(/元$/, "");
    res = res.replace(/^元/, "") || "零元";

    //返回最终结果
    return num < 0 ? "负" + res : res;
}

console.log(num2CNY(12345678.9));      //壹仟贰佰叁拾肆万伍仟陆佰柒拾捌元玖角
console.log(num2CNY(-123456.78));      //负壹万贰仟叁佰肆拾伍元柒角捌分
console.log(num2CNY(10000000000000));  //壹万亿元整
console.log(num2CNY(0.12));            //壹角贰分
console.log(num2CNY(0));               //零元