<div class="top-menu">
<ul class="nav pull-right top-menu">
<li><asp:button class="btn btn-theme04" id="btnLogOut" runat="server" xmlns:asp="#unknown">
Text="Log Out"
style="color:White; margin-top: 15px; margin-left:10px "
onclick="btnLogOut_Click" UseSubmitBehavior="False"></asp:button></li>
</ul>
</div>
USeSubmitBehaviour="False" Solved my problem
Thnks to all :)