In newer versions of Firefox, the javascript options to allow (or not) scripts to perform certain operations on the browser are accessible through
about:config
Prevent javascript from moving or resizing windows:
dom.disable_window_move_resize true: block script, false: allow script
Prevent javascript to raise or lower windows:
dom.disable_window_flip true: block script, false: allow script
Permit javascript to disable context menu (mouse right-click):
dom.event.contextmenu.enabled false: block script, true: allow script