I want my button when clicked the first time it starts the game and when I click it again remove h1 element. how can i do?

<button class='btn' onclick='myFunction()'>click on me</button>

function myFunction(){
     name = prompt('Your name:');
   h1 = document.createElement('h1');
   h1.innerText = 'Hi '+name+'!';
   document.body.appendChild(h1);
 }