|start `v3.2.0` | signature start callback function (refers to the beginning of a stroke) | none
|signing `v3.2.0`| the callback function being signed (refers to a stroke in progress) | event
|end `v3.2.0`| signature end callback function (refers to the end of a stroke) | none
| confirm | Click the confirm button to trigger the event callback function | Canvas and data URI displayed by signature image
| confirm | Click the confirm button to trigger the event callback function | `canvas and signature image display data URI,<br/>If not drawn, returns a tooltip and an empty data URI`
| clear | Click the re sign button to trigger the event callback function | -