js編寫函數，判斷一個字符串是否是 “可回文字符串”

js編寫函數，判斷一個字符串是否是 “可回文字符串”

      var str = "aabbccehgfhaasdhgfashdfhabcasd";
      var obj = {};
         for(var i=0;i<str.length;i++){
              if(obj[str[i]]){
              obj[str[i]]++;
        }else{
            obj[ str[i] ] = 1;
        }
    }
          console.log(obj);
          var newStr = "";
          for(var key in obj){
          newStr += key;
          }
          console.log(newStr);