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Engineering judgment: prefer the native HTML behavior described here before reaching for a custom widget.
Implementation note: Use radio groups for one choice, checkboxes for independent choices, and explicit button types. Keep the browser behavior observable while you work.
A useful way to learn this is to start with the browser's observable behavior, not the tag list. In this lesson, the focus is choice groups, button types, and submission behavior. That matters because HTML is interpreted by a parser and then exposed to browser features such as navigation, accessibility tooling, form controls, media handling, and script APIs. A correct-looking screenshot can still hide a poor document model.
<fieldset><legend>Plan</legend><label><input type="radio" name="plan" value="pro">Pro</label></fieldset>
Start with the smallest meaningful example. The working snippet demonstrates the core syntax, but the important part is what each piece contributes: the element supplies semantics or behavior, attributes refine that meaning, and surrounding structure gives the browser context. Don't add markup just because a framework or copied example happens to include it.
| Decision | Why it matters |
|---|---|
| Native element | Carries browser semantics and default behavior. |
| Attribute | Refines the element without replacing its meaning. |
| CSS/JS hook | Adds presentation or behavior around the existing structure. |
<label>Email<input type="email" name="email" required></label>
Don't confuse browser-side convenience with a security boundary. The markup in checkboxes, radio buttons, and buttons should improve behavior, but authoritative validation and policy belong at the trust boundary that processes the request.
Now put the same idea under pressure. A realistic failure is: Use radio groups for one choice, checkboxes for independent choices, and explicit button types. The browser may recover, ignore an invalid combination, or leave the user with a control that appears visually fine but behaves differently than expected. That is why source inspection and keyboard testing belong in the workflow.
A small, explicit HTML decision now is usually cheaper than a compatibility or accessibility workaround later.
Warning: invalid or overly permissive markup may still render. Rendering is not proof that the document model is correct.
Finish the lesson once you have worked through the material. This awards ★ 20 XP.