I would like to be able to programmatically invoke the right-click menu options, initiated from user events like rollover and whatnot of course. Is this possible?
Specifically, I would like to be able to call the Safari "Use Image as Desktop Picture" or the "Add Image to iPhoto Library", or the Firefox "Set as Desktop Background" using pure Javascript, so you don't have to right click. Is that possible?
You can't and this is because of security limitations.
If you could do that, malicious websites can access your browser and tamper with your system.
As far a I know, there is absolutely no way of doing this in a generic form using pure Javascript. You would have to build extensions (or maybe a Greasemonkey script for Firefox, I don't know) for each browser.
I seriously hope you can't do that... No website should be able to touch my desktop picture or iPhoto library.
来源：https://stackoverflow.com/questions/1896362/programmatically-calling-browser-right-click-menu-options