asp.net + js = problem with postback

Hi,
I'm new to js ( also using jquery ) with asp.net.
As usual, there's some problem ;-) 


Please look at this piece of code: 
.ascx file

<asp:Button ID="SaveFormButton" runat="server" Text="Save Form" onclick="SaveFormButton_Click" /> <asp:Button class="SaveForm" ID="SaveFormButton" runat="server" Text="Save Form" onclick="SaveFormButton_Click" />

cs.file 
 protected override void OnInit(EventArgs e)        {            base.OnInit(e);
            SaveFormButton.At ...