I'm using asp.net(C#) under visual studio 2010

I have a panel that is by default set 2 be hidden( visible=false)

I need to create a JavaScript function that would be executed on a button click to make this panel visible if hidden and hidden if visible.
and this should be client side, here is the code I have so far

   <script type=text/javascript>



    function func1()

    {

    i need this code please

    }



<asp:Panel ID=ResultsPanel runat=server>



Some controls



</asp:Panel>



<asp:button id=button1 runat=server onclick=javascript:func1()>Hide/Unhide</asp:button>