HTML Form Validation Without JavaScript

Required Fields

<input type="text" name="name" required />

The browser will stop the form from submitting if this field is empty.

Text Length Limits

<input type="text" name="username" minlength="3" maxlength="20" required />

Number Limits

<input type="number" name="age" min="18" max="99" required />

Pattern (Custom Format)

<input type="text" name="zip" pattern="[0-9]{5}" placeholder="12345" required />

This example only allows exactly 5 digits.

Email and URL Validation

<input type="email" name="email" required /> <input type="url" name="website" />

The browser automatically checks if the format looks correct.

Common Validation Attributes

Quick Tips

• Built-in validation improves user experience, but it’s not fully secure, always validate again on the server.
• Clear labels help users understand what went wrong.
• Keep pattern simple so it’s easy to maintain.
• Test your form in different browsers, because validation messages can look slightly different.
• With these HTML features, you can already make your forms much better before adding any JavaScript.