The redirect URL must be absolute HTTPS URL otherwise AMP will throw an error and redirection won't happen.
Known Issue: Due to an issue in Safari i OS redirecting to deep linked URLs (URLs that would actually end up opening a native app) might fail when the AMP document is embedded. provide polyfills for behaviors and functionality missing from some browsers or being implemented in the next version of CSS.
For “cancel” type buttons, the validation is normally skipped entirely.
Form validation takes two forms: field-level validation, pertaining to the value of an individual field, and form-level validation, pertaining to the form as a whole.
z3c.form’s field widget validators address these shortcomings.
These are specific to the form; by contrast, constraints are a feature of This registers an adapter, extending the Simple Field Validator base class, and calling the superclass version of validate() to gain the default validation logic.
“If the user agent supports letting the user submit a form implicitly (for example, on some platforms hitting the “enter” key while a text field is focused implicitly submits the form), then doing so for a form whose default button has a defined activation behavior must cause the user agent to run synthetic click activation steps on that default button.” “If the form has no submit button, then the implicit submission mechanism must do nothing if the form has more than one field that blocks implicit submission, and must submit the form element from the form element itself otherwise.
For the purpose of the previous paragraph, an element is a field that blocks implicit submission of a form element if it is an input element whose form owner is that form element and whose type attribute is in one of the following states: Text, Search, URL, Telephone, E-mail, Password, Date and Time, Date, Month, Week, Time, Local Date and Time, Number” handler on a button.
First on the native platform, in this example i OS, we create a Platform Effect.This is no problem if the interface exists only for the form, but could be a problem if it is used in other contexts as well.Second, if we want to re-use a validator for multiple forms, we would need to modify multiple schemata.Form-level validation is less common, but can be useful if fields have complex inter-dependencies.Constraints are relatively easy to write, but they have two potential drawbacks: First of all, they require that we change the underlying interface.Many users have an expectation that implicit submission will just work. Many sites do not have a submit button within the form.