金额大小写自动转换（代码来源于农行网银）

ChangeToBig.js

// 金额大小写自动转换
function ChangeToBig(value) {
    if (value == null || value == "") {
        //return "错误金额";
        return "";
    }

    value = "" + value;

    var intFen, i;
    var strArr, strCheck, nstrCheck, strFen, strDW, strNum, strBig, strNow;

    var v = -1;
    try {
        v = parseFloat(value);
    } catch (ex) {}

    if (isNaN(v) || v <= 0 || v > 999999999999.99) {
        return "错误金额";
    } else if (v >= 1 && value.charAt(0) == '0') {
        return "错误金额";
    } else if (value.charAt(0) == '+') {
        return "错误金额";
    }

    if (value.indexOf("e") >= 0 || value.indexOf("E") >= 0) {
        return "错误金额";
    }

    var strArray = value.split(".");
    if ((strArray.length == 2 && strArray[0] == "") || (strArray[1] && strArray[1].length > 2)) { //小数点后面超过两位提示
        return "错误金额";
    }

    try {
        i = 0;
        strBig = "";
        intFen = parseInt(value * 100 + 0.00099999999); //转换为以分为单位的数值
        strFen = intFen.toString();
        strArr = strFen.split(".");
        strFen = strArr[0];
        intFen = strFen.length; //获取长度
        strArr = strFen.split(""); //将各个数值分解到数组内                
        while (intFen != 0) //分解并转换
        {
            i = i + 1;
            switch (i) //选择单位
            {
                case 1:
                    strDW = "分";
                    break;
                case 2:
                    strDW = "角";
                    break;
                case 3:
                    strDW = "元";
                    break;
                case 4:
                    strDW = "拾";
                    break;
                case 5:
                    strDW = "佰";
                    break;
                case 6:
                    strDW = "仟";
                    break;
                case 7:
                    strDW = "万";
                    break;
                case 8:
                    strDW = "拾";
                    break;
                case 9:
                    strDW = "佰";
                    break;
                case 10:
                    strDW = "仟";
                    break;
                case 11:
                    strDW = "亿";
                    break;
                case 12:
                    strDW = "拾";
                    break;
                case 13:
                    strDW = "佰";
                    break;
                case 14:
                    strDW = "仟";
                    break;
            }

            switch (strArr[intFen - 1]) //选择数字
            {
                case "1":
                    strNum = "壹";
                    break;
                case "2":
                    strNum = "贰";
                    break;
                case "3":
                    strNum = "叁";
                    break;
                case "4":
                    strNum = "肆";
                    break;
                case "5":
                    strNum = "伍";
                    break;
                case "6":
                    strNum = "陆";
                    break;
                case "7":
                    strNum = "柒";
                    break;
                case "8":
                    strNum = "捌";
                    break;
                case "9":
                    strNum = "玖";
                    break;
                case "0":
                    strNum = "零";
                    break;
            }

            //处理特殊情况
            strNow = strBig.split("");
            //分为零时的情况
            if ((i == 1) && (strArr[intFen - 1] == "0")) {
                strBig = "整";
            }
            //角为零时的情况
            else if ((i == 2) && (strArr[intFen - 1] == "0")) { //角分同时为零时的情况
                if (strBig != "整")
                    strBig = "零" + strBig;
            }
            //元为零的情况
            else if ((i == 3) && (strArr[intFen - 1] == "0")) {
                strBig = "元" + strBig;
            }
            //拾－仟中一位为零且其前一位（元以上）不为零的情况时补零
            else if ((i < 7) && (i > 3) && (strArr[intFen - 1] == "0") && (strNow[0] != "零") && (strNow[0] != "元")) {
                strBig = "零" + strBig;
            }
            //拾－仟中一位为零且其前一位（元以上）也为零的情况时跨过
            else if ((i < 7) && (i > 3) && (strArr[intFen - 1] == "0") && (strNow[0] == "零")) {}
            //拾－仟中一位为零且其前一位是元且为零的情况时跨过
            else if ((i < 7) && (i > 3) && (strArr[intFen - 1] == "0") && (strNow[0] == "元")) {}
            //当万为零时必须补上万字
            else if ((i == 7) && (strArr[intFen - 1] == "0")) {
                strBig = "万" + strBig;
            }
            //拾万－仟万中一位为零且其前一位（万以上）不为零的情况时补零
            else if ((i < 11) && (i > 7) && (strArr[intFen - 1] == "0") && (strNow[0] != "零") && (strNow[0] != "万")) {
                strBig = "零" + strBig;
            }
            //拾万－仟万中一位为零且其前一位（万以上）也为零的情况时跨过
            else if ((i < 11) && (i > 7) && (strArr[intFen - 1] == "0") && (strNow[0] == "万")) {}
            //拾万－仟万中一位为零且其前一位为万位且为零的情况时跨过
            else if ((i < 11) && (i > 7) && (strArr[intFen - 1] == "0") && (strNow[0] == "零")) {}
            //万位为零且存在仟位和十万以上时，在万仟间补零
            else if ((i < 11) && (i > 8) && (strArr[intFen - 1] != "0") && (strNow[0] == "万") && (strNow[2] == "仟")) {
                strBig = strNum + strDW + "万零" + strBig.substring(1, strBig.length);
            }
            //单独处理亿位
            else if (i == 11) {
                //亿位为零且万全为零存在仟位时，去掉万补为零
                if ((strArr[intFen - 1] == "0") && (strNow[0] == "万") && (strNow[2] == "仟")) {
                    strBig = "亿" + "零" + strBig.substring(1, strBig.length);
                }
                //亿位为零且万全为零不存在仟位时，去掉万
                else if ((strArr[intFen - 1] == "0") && (strNow[0] == "万") && (strNow[2] != "仟")) {
                    strBig = "亿" + strBig.substring(1, strBig.length);
                }
                //亿位不为零且万全为零存在仟位时，去掉万补为零
                else if ((strNow[0] == "万") && (strNow[2] == "仟")) {
                    strBig = strNum + strDW + "零" + strBig.substring(1, strBig.length);
                }
                //亿位不为零且万全为零不存在仟位时，去掉万        
                else if ((strNow[0] == "万") && (strNow[2] != "仟")) {
                    strBig = strNum + strDW + strBig.substring(1, strBig.length);
                }
                //其他正常情况
                else {
                    strBig = strNum + strDW + strBig;
                }
            }
            //拾亿－仟亿中一位为零且其前一位（亿以上）不为零的情况时补零
            else if ((i < 15) && (i > 11) && (strArr[intFen - 1] == "0") && (strNow[0] != "零") && (strNow[0] != "亿")) {
                strBig = "零" + strBig;
            }
            //拾亿－仟亿中一位为零且其前一位（亿以上）也为零的情况时跨过
            else if ((i < 15) && (i > 11) && (strArr[intFen - 1] == "0") && (strNow[0] == "亿")) {}
            //拾亿－仟亿中一位为零且其前一位为亿位且为零的情况时跨过
            else if ((i < 15) && (i > 11) && (strArr[intFen - 1] == "0") && (strNow[0] == "零")) {}
            //亿位为零且不存在仟万位和十亿以上时去掉上次写入的零
            else if ((i < 15) && (i > 11) && (strArr[intFen - 1] != "0") && (strNow[0] == "零") && (strNow[1] == "亿") && (strNow[3] != "仟")) {
                strBig = strNum + strDW + strBig.substring(1, strBig.length);
            }
            //亿位为零且存在仟万位和十亿以上时，在亿仟万间补零
            else if ((i < 15) && (i > 11) && (strArr[intFen - 1] != "0") && (strNow[0] == "零") && (strNow[1] == "亿") && (strNow[3] == "仟")) {
                strBig = strNum + strDW + "亿零" + strBig.substring(2, strBig.length);
            } else {
                strBig = strNum + strDW + strBig;
            }

            strFen = strFen.substring(0, intFen - 1);
            intFen = strFen.length;
            strArr = strFen.split("");
        }
        if (strBig.indexOf("undefined") != -1) {
            return "错误金额";
        }
        return strBig;
    } catch (err) {
        return ""; //若失败则返回原值
    }
}