Attributes
Attributes opening tag ke andar likhe jaate hain: name="value" format mein — extra information dete hain tag ke baare mein. Har tag ke apne specific, commonly-used attributes hote hain (jaise <img> ka src/alt, <a> ka href).
Kuch attributes GLOBAL hain — kisi bhi tag par use ho sakte hain: id (unique identifier), class (styling/JS ke liye grouping), style (inline CSS), title (hover tooltip).
<img src="cat.jpg" alt="Ek cute billi">
<a href="https://example.com">Click here</a>
<!-- Global attributes: -->
<div id="header" class="main-nav">...</div>
<p title="Ye ek tooltip hai">Hover karo mujhpar</p>
<!-- Multiple attributes: -->
<input type="text" placeholder="Naam likho" required>- attribute="value" format, opening tag ke andar
- id = unique (ek page mein ek baar), class = shared/reusable
- Har tag ke apne specific attributes (src, href, type, etc.)
data-* attributes (jaise data-user-id="123") custom information store karne ke liye hain jo JavaScript baad mein use kar sake — standard HTML attributes na hone par bhi, ye valid aur safe way hai extra data attach karne ka.
<div data-user-id="123" data-role="admin">
User Card
</div>
<!-- JavaScript se access: -->
<!-- element.dataset.userId → "123" -->
<!-- element.dataset.role → "admin" -->Kuch attributes "boolean" hote hain — sirf unki PRESENCE hi matter karti hai, koi value nahi chahiye (jaise disabled, required, checked). required="required" likhna technically valid hai, lekin sirf required likhna kaafi hai.
<input type="text" required> <!-- required hai -->
<input type="text"> <!-- required nahi hai -->
<button disabled>Click Nahi Kar Sakte</button>
<input type="checkbox" checked>