js的精度运算方法

floatAdd: function(arg1, arg2) {
    var r1, r2, m;
    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));
    return (arg1 * m + arg2 * m) / m;
  },
  //减    
  floatSub: function(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    
  floatMul: function(arg1, arg2) {
    var m = 0,
      s1 = arg1.toString(),
      s2 = arg2.toString();
    try {
      m += s1.split(".")[1].length
    } catch (e) {}
    try {
      m += s2.split(".")[1].length
    } catch (e) {}
    return Number(s1.replace(".", "")) * Number(s2.replace(".", "")) / Math.pow(10, m);
  },
  //除   
  floatDiv: function(arg1, arg2) {
    var t1 = 0,
      t2 = 0,
      r1, r2;
    try {
      t1 = arg1.toString().split(".")[1].length
    } catch (e) {}
    try {
      t2 = arg2.toString().split(".")[1].length
    } catch (e) {}

    r1 = Number(arg1.toString().replace(".", ""));

    r2 = Number(arg2.toString().replace(".", ""));
    return (r1 / r2) * Math.pow(10, t2 - t1);
  },
  getDateTimeStamp:function(dateStr) {
    return Date.parse(dateStr.replace(/-/gi, "/"));
  }
})