Just by receiving focus, do not cause any situation change. An example of a malfunction that a modal window that opens automatically when receiving focus and a page movement occurs when receiving focus. Such behavior is difficult for users to predict and is hard to handle.
| Principle | Understandable | Information and the operation of user interface must be understandable. |
|---|---|---|
| Guideline | Predictable | Make Web pages appear and operate in predictable ways. |
| Criterion | On Focus (3.2.1 A) |
Neither component causes a change in context when it receives focus. |