基于jQuery实现文本框缩放以及上下移动功能_jquery

 $(function(){
          var $comment = $('#comment');
          $('.bigger').click(function(){
              if(!$comment.is(":animated")){
                  if($comment.height()                       //$comment.height($comment.height() + 50);
                      $comment.animate({height:"+=50"},400);
                  }
              }
          });
           $('.smaller').click(function(){
               if(!$comment.is(":animated")){
                   if($comment.height() > 50){
                       //$comment.height($comment.height() - 50);
                       $comment.animate({height:"-=50"},400);
                   }
               }
           });
           $('.up').click(function(){
              if(!$comment.is(":animated")){
                  $comment.animate({scrollTop:"-=50"},400);
              }
           });
           $('.down').click(function(){
               if(!$comment.is(":animated")){
                   $comment.animate({scrollTop:"+=50"},400);
               }
           });
       }); 

.bigger , .down , .up , .smaller{
    background-color: #f1a55c;
}