* dispatch event to take into account calculation order * use a map for actions in Field
* https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/js_api_reference.pdf#page=335 * it has all the properties/methods defined in the spec * unimplemented methods are there but with an empty body to avoid exception when calling an undefined method * implement zoom, zoomType, layout, pageNum, ...