JS精确计算

    //说明：javascript的加法结果会有误差，在两个浮点数相加的时候会比较明显。这个函数返回较为精确的加法结果。      //调用：accAdd(arg1,arg2)      //返回值：arg1加上arg2的精确结果          function accAdd(arg1, arg2) {          var r1, r2, m;          try {              r1 = (1 * arg1).toString().split(".")[1].length;          }          catch (e) {              r1 = 0;          }          try {              r2 = (1 * arg2).toString().split(".")[1].length;          }          catch (e) {              r2 = 0;          }          m = Math.pow(10, Math.max(r1, r2));          return (arg1 * m + arg2 * m) / m;      }                      //说明：javascript的减法结果会有误差，在两个浮点数相加的时候会比较明显。这个函数返回较为精确的减法结果。      //调用：accSub(arg1,arg2)      //返回值：arg1减上arg2的精确结果          function accSub(arg1, arg2) {          return accAdd(arg1, -arg2);      }                     //说明：javascript的乘法结果会有误差，在两个浮点数相乘的时候会比较明显。这个函数返回较为精确的乘法结果。      //调用：accMul(arg1,arg2)      //返回值：arg1乘以arg2的精确结果          function accMul(arg1, arg2) {          var m = 0, s1 = (1 * arg1).toString(), s2 = (1 * arg2).toString();          try {              m += s1.split(".")[1].length;          }          catch (e) {          }          try {              m += s2.split(".")[1].length;          }          catch (e) {          }          var ss = Number(s1.replace(".", "")) * Number(s2.replace(".", "")) / Math.pow(10, m);          return Math.round(ss * 100) / 100;      }                     //说明：javascript的除法结果会有误差，在两个浮点数相除的时候会比较明显。这个函数返回较为精确的除法结果。      //调用：accDiv(arg1,arg2)      //返回值：arg1除以arg2的精确结果          function accDiv(arg1, arg2) {          var t1 = 0, t2 = 0, r1, r2;          try {              t1 = (1 * arg1).toString().split(".")[1].length;          }          catch (e) {          }          try {              t2 = (1 * arg2).toString().split(".")[1].length;          }          catch (e) {          }          with (Math) {              r1 = Number((1 * arg1).toString().replace(".", ""));              r2 = Number((1 * arg2).toString().replace(".", ""));              var ss = (r1 / r2) * pow(10, t2 - t1);              return Math.round(ss * 100) / 100;          }      }      //金额大小写转换      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("Too large a number to convert!");        return "";      }      // http://www.knowsky.com/ 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;      outputCharacters = outputCharacters;      return outputCharacters;      }//       //还原金额         function rmoney(s){           return parseFloat(s.replace(/[^\d\.-]/g,""));        }                     //金额合计的格式化s为要格式化的参数（浮点型），n为小数点后保留的位数          function fmoney(s,n){          n = n>0 && n<=20 ? n : 2;          s = parseFloat((s+"").replace(/[^\d\.-]/g,"")).toFixed(n)+"";          var l = s.split(".")[0].split("").reverse(),           r = s.split(".")[1];           t = "";          for(i = 0;i<l.length;i++){              t+=l[i]+((i+1)%3==0 && (i+1) != l.length ? "," : "");           }          return t.split("").reverse().join("")+"."+r;      }