HTML Code

<!DOCTYPE html>

<html lang=en>

<head>

  <meta charset=UTF-8>

  <meta name=viewport content="width=device-width,initial-scale=1">

  <title>data-* dataset Example</title>

  <style>body{font-family:system-ui,sans-serif;margin:0;padding:1.5rem;background:#f8fafc;color:#334155;line-height:1.7}h1{margin:0 0 .75rem;font-size:1.25rem;color:#0f172a}button{font:inherit;padding:.45rem .85rem;margin-bottom:.75rem;border:1px solid #cbd5e1;border-radius:6px;background:#2563eb;color:#fff;cursor:pointer}.output{max-width:420px;padding:.85rem 1rem;background:#fff;border:1px solid #e2e8f0;border-radius:8px;font-size:.875rem}p{margin-top:1rem;font-size:.875rem;color:#64748b;max-width:420px}code{background:#e2e8f0;padding:.1rem .35rem;border-radius:4px}</style>

</head>

<body>

  <h1>Read and update with dataset</h1>

  <p id=user data-user-id=12345 data-username=john_doe>User Info</p>

  <button type=button id=updateBtn>Update username</button>

  <div class=output id=output>Click the button to read and change data-* values.</div>



  <script>var user=document.getElementById("user"),output=document.getElementById("output"),btn=document.getElementById("updateBtn");btn.addEventListener("click",(function(){var e=user.dataset.userId;user.dataset.username="new_username",output.innerHTML="User ID from <code>dataset.userId</code>: "+e+"<br>New username: "+user.dataset.username}))</script>

</body>

</html>

Lines: 0 | Characters: 0

Live Preview Auto-refresh on Run

HTML data-* Attribute — dataset in JavaScript