How to disable a button in Javascript and send its onclick event back

http://forums.asp.net/t/1211836.aspx
http://objectmix.com/javascript/112089-onclientclick-prevents-onclick-work.html


OnClientClick="javascript:DisableButton()"


 <script type="text/javascript">  
          function DisableButton()  
          {  
            <%=Page.GetPostBackEventReference(btn5 as Control)%>
            document.getElementById('<%=btn5.ClientID%>').disabled = true;                           
          }        
 </script>