JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <button id='start' onclick='test'>START</button>
    <div class="ligne" id="btnsup"></div>
</body>

JavaScript

function test()
{
    alert('test');
    handleClicks('btn_vito');
    handleClicks('btn_8p');
}



function  handleClicks(name_object) 
{
    
    
    
    var container = 'btnsup';


    document.getElementById(container).innerHTML += '<button id="' + name_object + '">'+name_object+'</button>';

    var name_object = 'btn_8p';
    var current = document.getElementById(name_object);
    current.onclick = function ()
    {
        alert(this.id);
    };
}