怎么理解这一句 http://www.imooc.com/code/3251

http://www.imooc.com/code/3251

• var hobby = document.getElementsByTagName("input");
              for(var i=0;i<hobby.length;i++){
                  hobby[i].checked=true;                ？？
           }

• for(var n=0;n<j.length;n++){
                     
                          hobby[(j.charAt(n))-1].checked=true;
                  }