Bummer! This is just a preview. You need to be signed in with an account to view the entire instruction.
- Client-side form validation
- Using Built-in Form Validation
- The Required Attribute
- Validating Against a Regular Expression
- Constraining the Length of Your Entries
- Full Example
- The Constraint Validation API
- Implementing a Customized Error Message
- A More Detailed Example
- Validating Forms Without a Built-in API
- Form Validation Quiz 6 questions
Well done!
You have completed (UPI) Chapter 10: Utilizing Forms with JavaScript!
Instruction
Validating Forms Without a Built-in API
In some cases, such as custom controls, you won't be able to or won't want to use the Constraint Validation API. You're still able to use JavaScript to validate your form, but you'll just have to write your own.
To validate a form, ask yourself a few questions:
- What kind of validation should I perform? You need to determine how to validate your data: string operations, type conversi...