HtmlInputFile类有个accept属性是干吗用的？

属性值
用逗号分隔的 MIME 编码列表。备注
使用该属性可以指定可被上载到服务器的文件类型。例如，若要将选择范围限制为图像，则将此属性设置为“image/*”。注意   对该属性的支持依赖于浏览器。请检查您的浏览器以确定它是否支持该属性。
示例
[Visual Basic, C#, JScript] 下面的示例说明如何使用 Accept 属性限制用户，使其不能选择除图像文件以外的任何文件。[Visual Basic]
<%@ Page Language="VB" AutoEventWireup="True" %><html>
<head>

    <script language="VB" runat="server">
    Sub Button1_Click(Source As Object, e As EventArgs)

        If Text1.Value = "" Then
            Span1.InnerHtml = "Error: you must enter a file name"
            Return
        End If

        If Not (File1.PostedFile Is Nothing) Then
            Try
                File1.PostedFile.SaveAs(("c:\temp\" & Text1.Value))
                Span1.InnerHtml = "File uploaded successfully to <b>c:\temp\" & _
                                      Text1.Value & "</b> on the Web server"
            Catch exc As Exception
                Span1.InnerHtml = "Error saving file <b>c:\temp\" & _
                                      Text1.Value & "</b><br>" & exc.ToString()
            End Try
        End If
    End Sub 'Button1_Click
  </script>

</head>
<body>

    <h3>HtmlInputFile Sample</h3>

    <form enctype="multipart/form-data" runat="server">

       Select File to Upload:
       <input id="File1"
              type="file"
              accept="image/*"
              runat="server"/>

       <p>
       Save as filename (no path):
       <input id="Text1"
              type="text"
              runat="server"/>

       <p>
       <span id=Span1
             style="font: 8pt verdana;"
             runat="server" />

       <p>
       <input type=button
              id="Button1"
              value="Upload"
              OnServerClick="Button1_Click"
              runat="server">

    </form>

</body>
</html>[C#]
<%@ Page Language="C#" AutoEventWireup="True" %><html>
<head>

    <script language="C#" runat="server">

       void Button1_Click(object Source, EventArgs e)
       {

          if (Text1.Value == "")
          {
             Span1.InnerHtml = "Error: you must enter a file name";
             return;
          }

          if (File1.PostedFile != null)
          {
             try
             {
                File1.PostedFile.SaveAs("c:\\temp\\"+Text1.Value);
                Span1.InnerHtml = "File uploaded successfully to <b>c:\\temp\\" +
                                  Text1.Value + "</b> on the Web server";
             }
             catch (Exception exc)
             {
                Span1.InnerHtml = "Error saving file <b>c:\\temp\\" +
                                  Text1.Value + "</b><br>" + exc.ToString();
             }
          }
       }

    </script>

</head>
<body>

    <h3>HtmlInputFile Sample</h3>

    <form enctype="multipart/form-data" runat="server">

       Select File to Upload:
       <input id="File1"
              type="file"
              accept="image/*"
              runat="server"/>

       <p>
       Save as filename (no path):
       <input id="Text1"
              type="text"
              runat="server"/>

       <p>
       <span id=Span1
             style="font: 8pt verdana;"
             runat="server" />

       <p>
       <input type=button
              id="Button1"
              value="Upload"
              OnServerClick="Button1_Click"
              runat="server">

    </form>

</body>
</html>[JScript]
<%@ Page Language="JScript" AutoEventWireup="True" %><html>
<head>

    <script language="JSCRIPT" runat="server">
    function Button1_Click(source : Object, e : EventArgs){

        if(Text1.Value == ""){
            Span1.InnerHtml = "Error: you must enter a file name"
            return
        }

        if(File1.PostedFile != null){
            try{
                File1.PostedFile.SaveAs(("c:\\temp\\" + Text1.Value))
                Span1.InnerHtml = "File uploaded successfully to <b>c:\\temp\\"
                                + Text1.Value + "</b> on the Web server"
            }catch(exc : Exception){
                Span1.InnerHtml = "Error saving file <b>c:\\temp\\"
                                + Text1.Value + "</b><br>" + exc.ToString()
            }
        }
    }
  </script>

</head>
<body>

    <h3>HtmlInputFile Sample</h3>

    <form enctype="multipart/form-data" runat="server">

       Select File to Upload:
       <input id="File1"
              type="file"
              accept="image/*"
              runat="server"/>

       <p>
       Save as filename (no path):
       <input id="Text1"
              type="text"
              runat="server"/>

       <p>
       <span id=Span1
             style="font: 8pt verdana;"
             runat="server" />

       <p>
       <input type=button
              id="Button1"
              value="Upload"
              OnServerClick="Button1_Click"
              runat="server">

    </form>

</body>
</html>[C++] 没有可用于 C++ 的示例。若要查看 Visual Basic、C# 或 JScript 示例，请单击页左上角的“语言筛选器”按钮。要求

我又不是没MSDN，这个属性真的能限定文件类型吗？还有楼下的，如何用别的方法限定文件类型不在本贴讨论范围内，我只想知道accept到底行不行

有时候用JS 的HTML 要很纯甚至和页面的 <! document.....>
都有关系把这些都去了再看看

我也想知道答案，程序的说明和MSDN上的演示感觉有冲突

File1.Accept="image/jpeg";
我也试了，不管用，怎么回事？？

调试易

HtmlInputFile类有个accept属性是干吗用的？

解决方案 »