版本：
文件：
- https://cdn.bootcdn.net/ajax/libs/jSignature/2.1.3/flashcanvas.js
- https://cdn.bootcdn.net/ajax/libs/jSignature/2.1.3/flashcanvas.min.js
- https://cdn.bootcdn.net/ajax/libs/jSignature/2.1.3/flashcanvas.swf
- https://cdn.bootcdn.net/ajax/libs/jSignature/2.1.3/jSignature.min.js
- https://cdn.bootcdn.net/ajax/libs/jSignature/2.1.3/jSignature.min.noconflict.js