HTML Forms & Input Validation

Forms are the primary data collection interface on the web. Built-in HTML5 validation reduces JavaScript, proper labelling enables accessibility, and correct input types improve mobile UX.

In this lesson

STEP 1

Every input must be associated with a <label> using the for/id pattern or by wrapping the input inside the label.

STEP 2

Use input type='email' to trigger native email validation and mobile keyboard layout.

STEP 3

The required attribute provides immediate validation without JavaScript.

Interactive Example

A properly labelled form field

Editable in-browser

Interactive Editor

typescript

· A properly labelled form field

Output Console

In-Browser Sandbox

Modify code and click "Run Code" (or ⌘+Enter) to evaluate output in real time.

What happens here?

<fieldset> groups related inputs; <legend> provides the group label.
The for attribute on <label> must match the id on <input>.
type='email' and required work together for native validation.

Quick check

Why should placeholder text never replace a label?

Next: Phase 2 Hands-On Drill

Ready to write code?

Solve the coding challenge in the in-browser IDE with live visible and hidden specification tests.