Keyboard shortcut for going to top or bottom of a page?
I find that the default zoom for typical PDF documents makes the text too small for comfortable reading. I always zoom in a little bit. As a result of that, I'm no longer viewing an entire page on the screen. I often have to press the down arrow key carefully until I can see the last line of text, making sure that I don't press it one too many times, making it jump to the next page.
What I really want is a keyboard shortcut which will "jump" to that point, so I can get there quickly without worrying about accidentally jumping to the next page. I also need a similar keyboard shortcut for the top of the page, mostly for when I'm reading multi-column articles.

