JSFiddle - React, Tailwind, and code Playground
HTML
<div id="maFen" align="center";>
<input name="monBouton3" id="monBouton3" type="button" onClick="$();"value="Ma Valeur X" />
</div>
JavaScript
$('#monBouton3').click(function() {
i = 3;
$('#monBouton'+i).css({"background-color": "#c9fa17"});
var arg = "monBouton" + i;
alert (arg);
alert ($('#monBouton'+i).val());
});