Its working fine.. May be problem with your datalist(no data). Verify it correctly.
Try below...
<style type="text/css">
#tabs li
{
list-style: none;
padding: 2px 10px;
border: solid 1px silver;
display: inline;
}
#content div
{
border: solid 1px silver;
}
</style>
<script src="http://code.jquery.com/jquery-1.6.3.min.js"></script>
<script type="text/javascript">
$(document).ready(function() {
$("#content div").hide();
$("#tabs li:first").attr("id", "current");
$("#content div:first").fadeIn();
$('#tabs a').click(function(e) {
e.preventDefault();
$("#content div").hide();
$("#tabs li").attr("id", "");
$(this).parent().attr("id", "current");
$('#' + $(this).attr('title')).fadeIn();
});
})();
</script>
<ul id="tabs">
<li><a href="#" title="tab1">One</a></li>
<li><a href="#" title="tab2">Two</a></li>
</ul>
<div id="content">
<div id="tab1">
<asp:DataList ID="DataList2" runat="server" GridLines="Both" DataKeyField="slno"
DataSourceID="SqlDataSource1" RepeatColumns="5">
<ItemTemplate>
slno:
<asp:Label ID="slnoLabel" runat="server" Text='<%# Eval("slno") %>' />
<br />
planname:
<asp:Label ID="plannameLabel" runat="server" Text='<%# Eval("planname") %>' />
<br />
price:
<asp:Label ID="priceLabel" runat="server" Text='<%# Eval("price") %>' />
<br />
</ItemTemplate>
</asp:DataList>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:constr %>"
SelectCommand="SELECT [slno], [planname], [price], [plantype], [advancerental], [monthlyrental] FROM [mobile_datacardplans]">
</asp:SqlDataSource>
Tab 1 body
</div>
<div id="tab2">
Tab 2 body
</div>
</div>
Hope it works...