Oh, that's bad. I have hardware acceleration of graphics disabled and although the tops of the lines are clipped, I don't get the extreme display that you get.

To experiment with the hardware acceleration setting (sensitive to display driver compatibility glitches), you can toggle it on and off first. You need to restart Firefox in order for this change to take effect, so save all work first (e.g., mail you are composing, online documents you're editing, etc.).

(WIN) orange Firefox button (or Tools menu) > Options > Advanced
(MAC) Firefox menu > Preferences > Advanced

On the "General" mini-tab, uncheck the box for "Use hardware acceleration when available"

Then exit/restart Firefox. Any difference?

My bad, I overlooked your OS. On Mac, the preference is here:

Firefox menu > Preferences > Advanced > "General" mini-tab

Changing the hardware acceleration did not make a difference.

Also, this is for a client, so ideally I'd like this to work for any user without having to change settings. Unfortunately, I did not create the PDF, so I do not currently have a way to adjust the original file.

Firefox 24 on WinXP here - onboard video drivers are so old that Hardware Acceleration isn't available.

I am seeing the same thing as the screenshot by jscher2000 shows. Readable but the top of the lettering is cropped / corrupted.

Works fine here with the latest dev version (0.8.554), so you can try this version to see if this is an issue that has been fixed.

Latest development version of the PDF Viewer (pdfjs) as a Firefox extension:

• http://mozilla.github.io/pdf.js/extensions/firefox/pdf.js.xpi

Latest version of the PDF Viewer extension on the Add-ons website (0.8.298).

• PDF Viewer: https://addons.mozilla.org/firefox/addon/pdfjs/