03. Form Validation
Introduction
Section titled “Introduction”Form validation ensures that users enter correct and complete data before submission. HTML5 provides built-in validation through attributes like required, pattern, min, max, and input types. Understanding form validation helps create better user experiences and prevents invalid data submission.
Built-in Validation
Section titled “Built-in Validation”required
Section titled “required”Makes field mandatory:
<input type="text" name="name" required>Input type validation:
<input type="email" name="email"><input type="url" name="website"><input type="number" name="age">pattern
Section titled “pattern”Custom validation pattern:
<input type="text" name="phone" pattern="[0-9]{10}">min and max
Section titled “min and max”Numeric limits:
<input type="number" name="age" min="18" max="100">minlength and maxlength
Section titled “minlength and maxlength”Text length limits:
<input type="text" name="username" minlength="3" maxlength="20">Validation Attributes
Section titled “Validation Attributes”novalidate
Section titled “novalidate”Disable validation:
<form novalidate> <!-- Form without validation --></form>formnovalidate
Section titled “formnovalidate”Disable validation for specific button:
<button type="submit" formnovalidate>Submit without validation</button>Best Practices
Section titled “Best Practices”Use Appropriate Input Types
Section titled “Use Appropriate Input Types”<input type="email" name="email" required><input type="tel" name="phone" pattern="[0-9]{10}">Provide Clear Error Messages
Section titled “Provide Clear Error Messages”<input type="email" name="email" required oninvalid="this.setCustomValidity('Please enter a valid email')">