Is there any API for firefox screenshot so that I can call it from plugin or js as a simpler solution?

I have a web app in which I have to take a screenshot of a particular div on button click and save in system as a portable softcopy (.png file) of the report. I have to also customize the view before the report image gets created and reset back once done. At current using firefox screenshot as it is difficult because there are few things in the app by default display, none or overflow hidden. hence if have to accommodate it then the first step would be press a expand all button then select screenshot and drag-select the region need to be converted to image hence I cant give this to the user. it should be one click download for users then it serves the purpose. If you have API for the plugin then that would be best. By this, I intend to restrict certain users to only use Firefox.