Masterpage And JQuery Creates Duplicate Content?

I have a ASP.Net masterpage with jQuery tabs.

I am trying to set it up like this:

<div id="tabs">
<ul>
<li><a href="Default.aspx">Home</a></li>
<li><a href="Settings.aspx"">Settings</a></li>
<li><a href="About.aspx">About</a></li>
</ul>
<div>
<asp:ContentPlaceHolder ID="Content" runat="server">
</asp:ContentPlaceHolder>
</div>
</div>

The contentplaceholder's div is inside the tab div to make the jQuery tabs surround the content. Unfortunately, jQuery duplicates all the content of the master page when turning this into real jQuery tabs:

<script>
$(document).ready(function () {
$("#tabs").tabs();
});
</script>

What can I do to avoid this?