The main problem is that if I press delete jConfirm fires,and completes delete button action without waiting for response.

function DeleteConFirmation() {

jConfirm('For this Week is allready scheduled do you wish to change the data?', 'Message', function (r) {
               if (r) {
                   return true;

               }
               else {
                   return false;
               }
           });

       }

<blockquote class="FQ"><div class="FQA">Quote:</div>
<asp:LinkButton ID="lnkDelete" runat="server"  CommandName="Delete"
   Text="Delete" OnClientClick="return DeleteConFirmation();"></asp:LinkButton>
</blockquote>