Examples
<asp:Button ID="btnNewSearch" runat="server" OnClientClick="javascript:location.reload();" Text="New Search" />
or
<input type="button" value="Reload Page" onClick="window.location.reload()">
<input type="button" value="Reload Page" onClick="history.go(0)">
<input type="button" value="Reload Page" onClick="window.location.href">