a标签获取自定义属性内容

 <li class="active"><a href="home.html" data="1" onclick="changeV(this)">通信技术工程</a></li>
 <li><a href="javascript:void(0)" data="2" onclick="changeV(this);return false">计算机科学</a></li>
                                    

   var subject = obj.getAttribute('data');   

  function changeV(obj) {
           var subject = obj.getAttribute('data');
           $.post({
               url:"${pageContext.request.contextPath}/user/findbooks",
               data:{'subject':subject},
               success:function (data) {
                   console.log(data);
                   var books = JSON.parse(data);
                   for(i=0;i<books.length;i++){
                       $("#photopath").attr('src',books[i].photopath);
                       $("#bookname").html(books[i].bookname);
                       $("#author").html(books[i].author);
                       $("#price").html(books[i].price);
                   }
               }
           })
       }