First of all, a click is triggered by a click, which is basically a mousedown followed by a mouseup in the same place, of the primary mouse button (usually left).
A right-click does not count as a click for the purposes of the event. However, it still registers mousedown and mouseup events, and you can check the Event.which property to see if it's the right mouse button being pressed. Alternatively, you may be able to use oncontextmenu, which in some cases can be considered the same as a right-click.
That still leaves the problem of a double-right-click, though. For this to work, you would need to measure the time between two right-clicks, and if you deem it short enough to be a double click, then handle it as such. It's a very complex setup, but double-right-clicks are not user-friendly at all so perhaps you should consider an alternative input?