問題描述

如果我問你，4330.61乘以100等於多少，我猜你肯定跟我說：“肯定是 433061”啊！
是啊，要我我也是這麽回答，來來來我們來看看瀏覽器怎麽說吧，如下圖

解決辦法

;(function(){
  function mathService(){
    this.add=function(a,b){
      var c, d, e;
      try {
        c = a.toString().split(".")[1].length;
      } catch (f) {
        c = 0;
      }
      try {
        d = b.toString().split(".")[1].length;
      } catch (f) {
        d = 0;
      }
      return e = Math.pow(10, Math.max(c, d)), (this.mul(a, e) + this.mul(b, e)) / e;
   }

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

   this.sub=function(a,b){
     var c, d, e;
     try {
       c = a.toString().split(".")[1].length;
     } catch (f) {
       c = 0;
     }
     try {
       d = b.toString().split(".")[1].length;
     } catch (f) {
       d = 0;
     }
     return e = Math.pow(10, Math.max(c, d)), (this.mul(a, e) - this.mul(b, e)) / e;
   }

   this.div=function(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(".", "")), this.mul(c / d, Math.pow(10, f - e));
   }
  }

  window.mathService=new mathService()

})(window);
 

來來來，用起來

Ok！寫完收工！！！

黃聰：JS數學計算精度修正