What are custom data attributes (data-*)?

Short answer: They allow you to store extra data on HTML elements — useful for scripts or dynamic behavior.

Example code

<button data-user-id="101" data-role="admin">View Profile</button> <script> const btn = document.querySelector("button"); console.log(btn.dataset.userId); // 101 console.log(btn.dataset.role); // admin </script> Key Takeaway: data-* attributes are perfect for embedding small pieces of custom data without affecting layout. Follow me on LinkedIn: Advanced

Real-world example (ShopNest)

ShopNest’s browser cart uses modern JavaScript: fetch APIs with async/await, modules, and clear error handling.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.