上传文件是点击出现该操作目标元件无效的错误

<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
        <title>多文件上传</title>
    <script language="JavaScript" type="text/javascript">
    function addFile()
    {
     var str = '<INPUT type="file" size="50" NAME="File">'
     document.getElementById('MyFile').insertAdjacentHTML("beforeEnd",str)
    }
    </script>
</head>
<body>
     <form id="form2" method="post" runat="server" enctype="multipart/form-data">
    <div>
      <h3>多文件上传</h3>
        <p id="P1"><input type="file" size="50" name="MyFile" /></p>
        <p>
          <input type="button" value="增加(Add)" onclick="addFile()" />
          <input onclick="this.form.reset()" type="button" value="重置(ReSet)" />
          <asp:Button Runat="server" Text="开始上传" ID="Button1"></asp:Button>
        </p>
        <p>
        <asp:Label id="strStatus" runat="server" ></asp:Label>
        </p> 
    </div>
    </form>
</body>
</html>

解决方案 »

  1.   

    file框怎么能修改innerHTML呢，改成下面这样就可以了
    <html xmlns="http://www.w3.org/1999/xhtml" >
    <head id="Head1" runat="server">
            <title>多文件上传</title>
        <script language="JavaScript" type="text/javascript">
        function addFile()
        {
         var str = '<INPUT type="file" size="50" NAME="File">'
         document.getElementById('P1').insertAdjacentHTML("beforeEnd",str)
        }
        </script>
    </head>
    <body>
         <form id="form2" method="post" runat="server" enctype="multipart/form-data">
        <div>
          <h3>多文件上传</h3>
            <p id="P1"><input type="file" size="50" name="MyFile" /></p>
            <p>
              <input type="button" value="增加(Add)" onclick="addFile()" />
              <input onclick="this.form.reset()" type="button" value="重置(ReSet)" />
              <asp:Button Runat="server" Text="开始上传" ID="Button1"></asp:Button>
            </p>
            <p>
            <asp:Label id="strStatus" runat="server" ></asp:Label>
            </p> 
        </div>
        </form>
    </body>
    </html>
      

  2.   

    <html xmlns="http://www.w3.org/1999/xhtml" >
    <head id="Head1" runat="server">
            <title>多文件上传</title>
        <script language="JavaScript" type="text/javascript">
        function addFile()
        {
         var str = '<INPUT type="file" size="50" NAME="File">'
         document.getElementById('MyFile').insertAdjacentHTML("afterEnd",str)
        }
        </script>
    </head>
    <body>
         <form id="form2" method="post" runat="server" enctype="multipart/form-data">
        <div>
          <h3>多文件上传</h3>
            <p id="P1"><input type="file" size="50" name="MyFile" /></p>
            <p>
              <input type="button" value="增加(Add)" onclick="addFile()" />
              <input onclick="this.form.reset()" type="button" value="重置(ReSet)" />
              <asp:Button Runat="server" Text="开始上传" ID="Button1"></asp:Button>
            </p>
            <p>
            <asp:Label id="strStatus" runat="server" ></asp:Label>
            </p> 
        </div>
        </form>
    </body>
    </html>