Here you can find out  firefox browser shortcut keys
CTRL + A  :Select all text on a webpage
CTRL + B  :Open the Bookmarks sidebar
CTRL + C  :Copy the selected text to the Windows clipboard
CTRL + D  :Bookmark the current webpage
CTRL + F  :Find text within the current webpage
CTRL + G  :Find more text within the same webpage
CTRL + H :Opens the webpage History sidebar
CTRL + I  :Open the Bookmarks sidebar
CTRL + J :Opens the Download Dialogue Box
CTRL + K :P laces the cursor in the Web Search box ready to type your search
CTRL + L :P laces the cursor into the URL box ready to type a website address
CTRL + M :Opens your mail program (if you have one) to create a new email message
CTRL + N :Opens a new Firefox window
CTRL + O :Open a local file
CTRL + P :P rint the current webpage
CTRL + R :Reloads the current webpage
CTRL + S :Save the current webpage on your PC
CTRL + T :Opens a new Firefox Tab
CTRL + U :View the page source of the current webpage
CTRL + V :P aste the contents of the Windows clipboard
CTRL + W :Closes the current Firefox Tab or Window (if more than one tab is open)
CTRL + X :Cut the selected text
CTRL + Z :Undo the last actionWindows Keyboard Shortcuts for Mozilla Firefox
Functional Keys:
F1 :Opens Firefox help
F3 :Find more text within the same webpage
F5 :Reload the current webpage
F6 :Toggles the cursor between the address/URL input box and the current webpage
F7 :Toggles Caret Browsing on and off. Used to be able to select text on a webpage with the keyboard
F11 :Switch to Full Screen mode