<script  runat="server">
sub submit(sender As Object, e As EventArgs)
lbl1.Text=txt1.Text
end sub
</script>

<html>
<body>

<form runat="server">
<asp:TextBox id="txt1" Text="Hello World!"
Font_Face="verdana" BackColor="#0000ff"
ForeColor="white" TextMode="MultiLine"
Height="50" runat="server" />
<asp:Button OnClick="submit"
Text="把文本复制到 Label" runat="server" />
<p><asp:Label id="lbl1" runat="server" /></p>
</form>

</body>
</html>