<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script> <!--Jquery CDN-->
<script type="text/javascript">
$(document).ready(function(){
$(".buton_goster").click(function(){
$("div.divId").toggle();
});
});
</script>

<button class="buton_goster"></button>
<div class="divId">Açıldım</div>