Fields are validated on blur. If a field is already invalid, its validity is checked on each key input so that the user gets immediate feedback when the field is again valid.
A required field cannot be left empty.
The pattern
property specifies a regular expression that the element’s value is
checked against.
Extend Vaadin.TextFieldElement
to create your own custom element,
then override the checkValidity()
method to validate the user’s input.
Extend Vaadin.TextFieldElement
to create your own custom element,
then override the checkValidity()
to make your asynchronous validation,
and finally set the invalid
flag appropriately in the callback.