JS计算不准确问题解决方法

/**
 * 加法
 * @param a
 * @param b
 * @returns {Number}
 */
function accAdd(a, b) {
    var c, d, e;
    if(undefined==a||null==a||""==a||isNaN(a)) {
        a=0;
    }
    if(undefined==b||null==b||""==b||isNaN(b)) {
        b=0;
    }
    try {
        c = a.toString().split(".")[1].length;
    } catch (f) {
        c = 0;
    }
    try {
        d = b.toString().split(".")[1].length;
    } catch (f) {
        d = 0;
    }
    e = Math.pow(10, Math.max(c, d));
    return  (floatMul(a, e) + floatMul(b, e)) / e;
}

/**
     * 减法
     * @param arg1
     * @param arg2
     * @returns
     */
    accSub(arg1, arg2) {
      var r1, r2, m, n;
      try {
        r1 = arg1.toString().split(".")[1].length;
      } catch (e) {
        r1 = 0;
      }
      try {
        r2 = arg2.toString().split(".")[1].length;
      } catch (e) {
        r2 = 0;
      }
      m = Math.pow(10, Math.max(r1, r2));
      //动态控制精度长度
      n = (r1 >= r2) ? r1 : r2;
      return ((arg1 * m - arg2 * m) / m).toFixed(n);
    },

  /***
     * 乘法
     * @param arg1
     * @param arg2
     * @returns
     */
    accMul(arg1, arg2) {
      var m = 0,
        s1 = arg1.toString(),
        s2 = arg2.toString();
      try {
        m += s1.split(".")[1].length
      } catch (e) {console.log(e)}
      try {
        m += s2.split(".")[1].length
      } catch (e) {console.log(e)}
      return Number(s1.replace(".", "")) * Number(s2.replace(".", "")) / Math.pow(10, m);
    },

function accDiv(a, b) {
    var c, d, e = 0,
        f = 0;
    try {
        e = a.toString().split(".")[1].length;
    } catch (g) {}
    try {
        f = b.toString().split(".")[1].length;
    } catch (g) {}
    return c = Number(a.toString().replace(".", "")), d = Number(b.toString().replace(".", "")),  accMul(c / d, Math.pow(10, f - e));
}

  /**
     * 四舍五入保留两位小数
     */
    accRound(num) {
        return Math.round(num*100)/100
    },