avoid page refresh on linkbutton click

hi all

i am using a link button in first.aspx page

dialog box is opening on link button click but first.aspx page is refresing 

how to avoid first.aspx page refresh on linkbutton click

my code is

<asp:ScriptManager ID="ScriptManager1" runat="server" ></asp:ScriptManager>

<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional" >
<ContentTemplate>
<table class="table table-striped table-hover">
<tr>
<td>
<asp:Label ID="Label3" runat="server" Text="Industrial Area Name"></asp:Label>
</td>
<td>
<asp:dropdownlist ID="ddlindusarea" runat="server" class="form-control" AutoPostBack="True" OnSelectedIndexChanged="ddlindusarea_SelectedIndexChanged" >
<asp:ListItem>Select</asp:ListItem>
</asp:dropdownlist>
</td>


<td>
<asp:LinkButton ID="ibtndetails" class="mdi-action-description" Width="25%" Height="25%" OnClick="ibtndetails_Click" runat="server"/>
</td>
</tr>
</table>
</ContentTemplate>
<Triggers>
<asp:PostBackTrigger ControlID="ibtndetails" />
</Triggers>
</asp:UpdatePanel>