Document Dom

<!DOCTYPE html>
<html lang="en">
<head>
  
</head>
<body>

   <h1>Welcome To CloseTag.com</h1>
   <button type="button" id="button">Try It</button>
   <p id="result"></p>
    <script>
    let button = document.getElementById('button');
    let result = document.getElementById('result');
    let headContent = document.head; 
    button.addEventListener("click",()=>{
    headContent.innerHTML = "<title>Page Title</title>";
    result.innerHTML = headContent.innerText;
    });
    </script>
  
</body>   
</html>