Make Firefox Window View Full Screen In Mac

I phrased the title like that because I used all those words,

Make Firefox Window View Full Screen In Mac,

plus the word bigger in my search.  I found this link, which basically says make a book mark, put it in the bookmark bar up @ the top.  For location paste this in, (if it doesn't give you the option to edit location, right click, go to properties and voila put location in)

javascript:self.moveTo(0,0); self.resizeTo(screen.availWidth,screen.availHeight);

And put it all in ONE LINE, OK?  Oh and BTW I have a mac from 2005 and os 10.39 so I'm upgrading soon but that's what I'm running.  Newer firefox and os 10 versions may have this built in.

Click on the bookmark in the bookmark bar, the bookmark that you have hopefully named something like Firefox Big or something catchy like that, and you can live life normally again.