使用DOM插入新节点后不显示？


<head runat="server">
    <title>向文档添加内容</title>
    <script type="text/javascript">
        function AddContent()
        {
            var container = document.createElement("table");
            var tbody = document.createElement("tbody");
            var headline = document.createElement("tr");
            var firsttd = document.createElement("td");
            var secondtd = document.createElement("td");
            
            firsttd.appendChild(document.createTextNode("JavaScpt"));
            secondtd.appendChild(document.createTextNode(".NET Framwork"));
            
            headline.appendChild(firsttd);
            headline.appendChild(secondtd);
tbody.appendChild(headline);
            container.appendChild(tbody);
                        
            document.body.appendChild(container);           
        }
    </script>
</head>
<body>
    <form id="form1" runat="server">
        <div>
            <button onclick="AddContent()">
                Add Content to a Document</button>
        </div>
    </form>
</body>