DOM support for validity, with a validity attribute for form elements, and a new invalid event.
验证的DOM支持，为表单元素增加了validity属性和新的invalid事件。
2
Based on the consistency with and coverage of these event constraints by the event sequences produced by the program execution, the validity of the distributed implementation can be tested.
Let us waive any questions concerning the validity of the principle that every event has a cause for though the question is important its discussion would lead us far afield.