ASP.NET Drop Down Listbox doesn't work in Opera Browser

[daonho]

I've been trying to figure out this problem for so long but no luck. The problem is that I have a ASP.NET Drop Down Listbox with a few item in there, and whenever I select an item from the listbox, I want to display its value in a label. The problem is that this code work properly in both IE and Firefox but not OPERA. It seems like Opera browser doesn't suppose the autopostback attribute of the drop down list. So, it doesn't do anything when I select item from drop down list. Anyone know how to deal with this problem?

 
<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="true">
<asp:ListItem>Item 1</asp:ListItem> 
<asp:ListItem>Item 2</asp:ListItem>
<asp:ListItem>Item 3</asp:ListItem>
<asp:ListItem>Item 4</asp:ListItem>
<asp:ListItem>Item 5</asp:ListItem>
</asp:DropDownList>
&nbsp;<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
 

----------- CODE ---------------------

 
Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList1.SelectedIndexChanged
Label1.Text = DropDownList1.SelectedValue.ToString
 
Page_Load(Nothing, Nothing)
 
End Sub
 
Protected Sub DropDownList1_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList1.TextChanged
Label1.Text = DropDownList1.SelectedValue.ToString
Page_Load(Nothing, Nothing)
End Sub