Visibility turns to none after postback automatically

[LauraD]

I tried to make the visibility of a div through javascript.\[code\] <asp:LinkButton class="ProfilePageDetailLinks" ID="lbtnPersonal" runat="server" OnClientClick="VisibleTab('PersonalDetails')">Show Details</asp:LinkButton> <div id="PersonalDetails"> <asp:UpdatePanel ID="UpdatePanel1" runat="server"> <ContentTemplate> </ContentTemplate> </asp:UpdatePanel> </div>function VisibleTab(str) { if (document.getElementById(str).style.display == 'none') { document.getElementById(str).style.display = 'block'; } else { document.getElementById(str).style.display = 'none'; }\[/code\]But after the postback, the div is hiding automatically.