• Javascript
• Développement front-end

<div id="1" class="button">
    <button id="button_1" >Button_1</button>
</div>
<button onclick="add();">Add</button>

<script type="text/javascript">
    function add(){
        var count = document.querySelectorAll('.button').length;
        var newCount = count+1;
        var elDiv = document.createElement('div');
        elDiv.setAttribute("id", newCount);
        elDiv.setAttribute("class", "button");
        elDiv.innerHTML = '<button id="button_"+newCount+">Button_'+newCount+"</button>";

        document.getElementById(count).appendChild(elDiv);
    }
</script>