hey i want to add to my game an option that the player will be able to snap the screen of the game and share it on facebook by pushing a button or even download it as a pic file someone know how can i do it??
Could paste all your game into a canvas object (see plugins). (that's for the snap part)
For the sharing part you need a way to send image data in an ajax query. But as the default Ajax object use Get method I don't think you have enough room to send any screen size image. There's an Ajax plugin that use POST method somewhere in the plugin list but you still need a way to convert your canvas into image data and probably a php page to interprete it. And remember. I can be totally wrong with the sharing part but for the snap part that's how I would do it.
It should be possible by a plugin actually - a plugin could call toDataURL() on the main canvas and download a PNG of whatever the canvas is showing. You may not be able to copy it to the clipboard, but you could download it or upload it somewhere else.