JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="menu">
	<li id="idA" class="classeActive" onclick="swap('partieA')";>Du Aaa</li>
	<li id="idU" onclick="swap('partieU')";>Du Uuu</li>
</ul>
<div id="partieA">blabla</div>
<div id="partieU">blublu</div>

CSS

#menu li{list-style:none; cursor:pointer;}
#partieA{display:block;}
#partieU{display:none;}
.classeActive{background-color:red;}

JavaScript

function swap(idPartie)
	{
		switch(idPartie)
		{
			case "partieA":
				document.getElementById("partieA").style.display="block";
				document.getElementById("partieU").style.display="none";
                document.getElementById("idA").className="classeActive";
                document.getElementById("idU").className="";
				break;
			case "partieU":
				document.getElementById("partieA").style.display="none";
				document.getElementById("partieU").style.display="block";
                document.getElementById("idA").className="";
                document.getElementById("idU").className="classeActive";
				break;
			default:
				document.getElementById("partieA").style.display="block";
				document.getElementById("partieU").style.display="none";
                document.getElementById("idA").className="classeActive";
                document.getElementById("idU").className="";
				break;
		}
	}