function selflog_show(id)为什么就是调用不了~~

 代码如下：
<script type="text/javascript">
     function sub(){
     var num=parseInt(document.getElementById("purchasenum").value);
     if(num>1){
     document.getElementById("purchasenum").value=--num;
     }
     }

     function add(){
     var num=parseInt(document.getElementById("purchasenum").value);
     if(num<100){
     document.getElementById("purchasenum").value=++num;
     }
     }

     function selflog_show(id){
     var num=document.getElementById("purchasenum").value;
     J.dialog.get({id:'haoyue_creat',title:'购物成功',width: 600,height:400, link:'<%=path%>/servlet/CartServlet?id='+id+'&num='+num+'CartAction=add',cover:true});

     }

     </script>


        body中的代码：
        <h2><%=i.getName()%></h2>
                                <p>商品ID=<%=i.getId()%></p>

                                <span>
                                    <span>￥<%=i.getPrice()%></span><br><br><br>
                                    <!-- <label>数量:</label> -->
                                    数量：

                                    <span id="sub" onclick="sub();">-</span>
                                    <span id="add" onclick="add();">+</span>
                                    <input type="text" name="purchasenum" id="purchasenum"  value="1" />




                                    <a href="javaScript:selflog_show(<%=i.getId()%>)">
                                    <button type="button" class="btn btn-fefault cart">
                                        <i class="fa fa-shopping-cart"></i>
                                        加入购物车
                                    </button>
                                    </a>



                                    <!-- 
                                    <button type="button" class="btn btn-fefault cart">
                                        <i class="fa fa-shopping-cart"></i>
                                        加入购物车
                                    </button>
                                     -->

                                </span>
                                <p><b>库存:</b> <%=i.getStock()%></p>
                                <p><b>产地:</b> <%=i.getCity()%> </p>



                        <%} %>

    出现的错误如下：

    一旦点击“加入购物车” 出现：

Goods_Details.jsp?id=1:58 Uncaught ReferenceError: J is not defined
at selflog_show (Goods_Details.jsp?id=1:58)
at :1:1

    bootstrap.min.js:7 Uncaught TypeError: Cannot read property 'offsetWidth' of undefined
at b.slide (bootstrap.min.js:7)
at b.next (bootstrap.min.js:7)
at i (jquery.js:4)

拜托各位啦