<body>
  <p> Question : qui est l'auteur du document intitulé "First Draft of a Report on the EDVAC" </p>
  <p>Réponse :
    <span id="reponse"></span> 
  </p>
  <button type="button" id="affiche">Afficher</button>
  <button type="button" id="cache">Cacher</button>
</body>
#reponse{
  color: navy;
  font-weight: normal;
}
body {
  background-color: cadetblue;
  color: white;
  margin: 20px;
  font-family: optima, arial;
}
let reponse = document.querySelector("#reponse");

let afficheBtn = document.querySelector("#affiche");
afficheBtn.addEventListener("click", afficher);

let cacheBtn = document.querySelector("#cache");
cacheBtn.addEventListener("click", cacher);

function afficher(){
  reponse.textContent="John von Neumann"
}
function cacher(){
  reponse.textContent=" "
}

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