应怎样加注释？

Question

每句都表示什么意思？<script type="text/javascript">      var index = 0;      var imgnum = $('.banner ul li').length;      var nmun='';      var imgwidth = $('.banner ul li').width();      var allimgwidth = imgwidth*imgnum;      $('.banner ul').css('width',allimgwidth);      $('.banner').hover(function(){             clearInterval(p);             $('.banner .u').fadeIn();      },function(){             pic();             $('.banner .u').fadeOut();      });      function pic(){             p=setInterval(function(){                    index++;                    if(index>=imgnum){                    index=0;                    }                    selectimg(index);             },3000);      }      function selectimg(index){             $('.banner ul').animate({'margin-left':'-' + imgwidth*index + 'px'},600);             $('.con a').eq(index).addClass('active').siblings('a').removeClass('active');      }      $('.banner .left').click(function(){             index-=1;             if(index<0){                    index=imgnum-1;             }             selectimg(index);      });      $('.banner .right').click(function(){             index+=1;             if(index>imgnum-1){                    index=0;             }             selectimg(index);      });      for(var ni=0;ni<imgnum;ni++){             nmun +="<a href='javascript:;'></a>";      }      $('.banner .con').html(nmun);      $('.banner .con a').eq(0).addClass('active');      $('.con a').each(function(i){             $(this).click(function(){                    index=i;                    $('.banner ul').animate({'margin-left':'-' + imgwidth*i + 'px'},600);                    $('.con a').eq(index).addClass('active').siblings('a').removeClass('active');             });      });        pic();</script>