innerHTML动态添加input，提交时无法获取其中的值

可以动态生成input.可是为什么取不到他的值？这个和innerHtml有关系吗<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="KeChengEdit.aspx.cs" Inherits="Test.KeChengEdit" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <script type="text/javascript">        function add()
        {
            var ii = 0;
            ii = getInput_zjCount();
            //            var newinput = document.createElement("input");
            //            newinput.nodeName = 'zj' + ii;
            //            updiv.appendChild(newinput);
            var str = window.updiv.innerHTML;
            var inputstr = '章节' + ii + ':<input type=text  name=zj' + ii + ' /><br/> ';
            window.updiv.innerHTML += inputstr;
           // window.updiv.appendChild            // alert("共有" + ii + "个input");
        }        function getInput_zjCount()
        {
            var inputCout = 0;
            var i = 1;
            var s = document.getElementsByName("zj" + i);
            while (s.length != 0)
            {
                i++;
                s = document.getElementsByName("zj" + i);
            }
            return i;
        }
    </script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <input type="hidden" name="editString" value="edit" />
        <input type="hidden" name="ID" value="<%# IDValue%>" />
        课程：<input type="text" id="input_kecheng" name="input_kecheng" runat="server" /><br />
        学院：<input type="text" id="input_xueyuan" name="input_xueyuan" runat="server" /><br />
        教师：<input type="text" id="input_teacher" name="input_teacher" runat="server" /><br />
        专业：<input type="text" id="input_zhuanye" name="input_zhuanye" runat="server" /><br />
        <div id="kechengInfo">
            章节信息：&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<input type="button" value="添加章节信息" onclick="javascript:add()" /><br />
            <div id="updiv">
                <%# sb.ToString()%>
            </div>
        </div>
        <br />
        <input type="submit" value="编辑" />
    </div>
    </form>
</body>
</html>
inputjavascript