<script type="text/javascript">
            $(function () {
                $("#btntest").bind("click", function () {
               
                    $("#btntest").toggle(
                        function(){
                            $("div").css("display","none");
                        },
                        function(){
                            $("div").css("display","block");
                            }
                    )  
                       
                       
                })
            });