Number.prototype.toFixed = function (d) {
  var s=this+"";
  if(!d)d=0;
  if(s.indexOf(".")==-1)s+=".";
  s+=new Array(d+1).join("0");
  if(new RegExp("^(-|\\+)?(\\d+(\\.\\d{0,"+(d+1)+"})?)\\d*$").test(s)){
      var s="0"+RegExp.$2,pm=RegExp.$1,a=RegExp.$3.length,b=true;
      
 
if(a==d+2){
          a=s.match(/\d/g);
          if(parseInt(a[a.length-1])>4){
              for(var i=a.length-2;i>=0;i--){
                  a[i]=parseInt(a[i])+1;
                  if(a[i]==10){
                      a[i]=0;
                      b=i!=1;
                  }else break;
              }
          }
          s
 
=a.join("").replace(new RegExp("(\\d+)(\\d{"+d+"})\\d$"),"$1.$2");

      }if(b)s=s.substr(1);
      return (pm+s).replace(/\.$/,"");
  }return this+"";

}

修改後