Validation
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* Basic Validation

  * Validating an Element

  * Validating Entire Forms At Once

  * Optional Elements

  * Validation Signals

* Custom Validation

  * Custom Validation Basics

  * Validation Phases

  * Short-Circuiting Descent Validation

  * Messaging

  * Normalization

  * Validation "state"

  * Examining Other Elements

  * Short-Circuiting Validation

* Validator API

  * Customizing Validators

  * Message Templating

  * Message Pluralization

  * Message Internationalization

  * Dynamic Messages

  * The Validator Class

* Included Validators

  * Scalars

  * Containers

  * Numbers

  * Email Addresses

  * URLs
