From MozillaZine Knowledge Base
You can allow scripts on web pages to take certain actions by checking the appropriate boxes, or you can prevent the actions by unchecking these settings:
Move or resize existing windows: Allows scripts to change the size or position of the existing window.
Raise or lower windows: Allows scripts to place windows underneath or on top of other windows.
Disable or replace context menus: Allows scripts to disable or change context (right-click) menus.
Hide the status bar: Allows scripts to hide the status bar, as in popup windows.
Change status bar text: Allows scripts to replace the status bar web address (URL) with scrolling text.
These settings were removed in Firefox 23 but you can use about:config to change the related preference settings, as follows: 
Allow scripts to:
[X] Move or resize existing windows: Uncheck this option/preference to disable moving and resizing windows using scripts.
[ ] Raise or lower windows: Uncheck this option/preference to make sure scripts cannot raise (bring to the front) or lower (send to the back) windows.
[X] Disable or replace context menus: Uncheck this option/preference to prevent web pages from disabling or changing the Firefox context menu.