[RESOLVED] jQuery: Clicking anywhere but on a particular button

[zhshqzyc]

I want to triggle a function by clicking anywhere except an asp.net button.

<script>
        $(document).ready(function () {
            $(document).click(function () {
                ValidateUserName();
            });
        });

and

<asp:Button ID="btnSave" runat="server" Text="SaveChanges" OnClick="btnSave_Click" />

How to modify my javascript code?
Thanks.