这个sport代表的是什么

  <script type="text/javascript">
            $(function () {
                $("#btnShow").bind("click", function () {
                   
                   
                    var $this = $(this);
                    
                    
                    $.getJSON("http://www.imooc.com/data/sport.json",function(data){
                        
                        
                        $this.attr("disabled", "true");
                        
                        
           $.each(data, function (index, sport) {
                if(index==4)
                 $("ul").append("<li>" +sport["name"] + "</li>");
                        
                            
                            
                        });
    
                    });
                });
            });
        </script>