Required Email Validation

A join form adds an email input with built-in browser constraints before exposing the submit action.

Program

HTML form constraints are declarative. The browser can validate an email field before the request is submitted.

required_email_validation.html

<form action="/join" method="post">
  <label for="email">Email</label>
  <input id="email" name="email" type="email" required>
  <button>Join</button>
</form>

type email The email input type asks the browser to validate email-shaped text.

required The required attribute prevents an empty value from passing constraint validation.