Pattern and format validation ensures that user input follows a specific structure.
It is used to validate data such as email addresses, phone numbers, PIN codes, and passwords.
Built-in Input Types for Validation
HTML provides special input types that automatically validate common formats.
Examples include email, url, number, and tel.
The browser automatically checks whether the entered value matches the expected format.
The pattern Attribute
The pattern attribute allows you to define a custom validation rule using a regular expression.
This pattern ensures that only a 10-digit number is accepted.
Password Format Validation
Patterns are often used to enforce strong passwords.
This pattern requires:
- At least one uppercase letter
- At least one lowercase letter
- At least one number
- Minimum 8 characters
Using the title Attribute for Guidance
The title attribute shows a helpful message when validation fails.
Best Practices for Pattern Validation
- Keep patterns simple
- Always guide users with clear messages
- Combine with required and length constraints
Why Pattern Validation Matters for Jobs
Professional applications rely on format validation to prevent bad data.
Employers expect developers to use patterns correctly in forms.
Practice Task
Create a form that validates:
- Email address
- Phone number using pattern
- Strong password using pattern
What You Will Learn Next
In the next lesson, you will learn how browsers display validation messages and how to guide users effectively.