Didn't work for me either... Rated 1 out of 5 stars

Fitting i guess: even Mozilla indirectly admits their pdf display is garbage ["This may not display properly..." You got that right!], so their extension inherits Firefox's apparent inability to display pdf text without mangling.
At any rate, like the .epub extensions, it's junk.

This review is for a previous version of the add-on (0.8.649). 

Did not work Rated 1 out of 5 stars

Could I give this a 0 rating? It simply did not work. I have no other pdf related add on or plugin and this did not supply functionality. No idea what went wrong.

This review is for a previous version of the add-on (0.8.649). 

Great PDF Viewer Rated 5 out of 5 stars

A very light and fast PDF Viewer

This review is for a previous version of the add-on (0.8.649). 

Rated 5 out of 5 stars

Please add the functionality to select a word by double-click.

This review is for a previous version of the add-on (0.8.649). 

classic Rated 5 out of 5 stars

This addon is pure classic. Deserves a medal for viewing pdf files

This review is for a previous version of the add-on (0.8.649). 

Does it work really ? Not working for me Rated 2 out of 5 stars

I've just installed. No icon, it seems that this add is not working.

I've Sumatra pdf plugin already installed, maybe a conflict. I don't know, it doesn't work for me.

This review is for a previous version of the add-on (0.8.649). 

Rated 5 out of 5 stars

PDF Viewer is getting better and better. This version of Mozilla Labs' PDF Viewer is in my opinion worth replacing a PDF readers' plug-ins as well as Google Docs as PDF viewer.
I did some testing with PDF files on the Web and didn't see any problem. I even think that the font quality is higher than that of Google's. I'll be sticking with this Mozilla PDF Viewer.

This review is for a previous version of the add-on (0.8.649). 

Rated 4 out of 5 stars

A built-in pdf viewer. Only drawback is if you want to simply download the .pdf, when you click on the pdf link, it automatically opens it in the next tab and you need to wait for a little to be fully loaded and finally press download button to finally start the downlaod.

This review is for a previous version of the add-on (0.8.649). 

Rated 4 out of 5 stars

Great Add-on, would like to see support for Thunderbird or SeaMonkey (^_^)

This review is for a previous version of the add-on (0.8.649). 

Can't deal correctly with embedded fonts Rated 2 out of 5 stars

Unfortunately it seems to have problems with embedded fonts. While certain PDFs we created here display nice in Adobe Reader they look quite ugly when displayed using this viewer. As it has become standard application for PDF in Firefox 19+ (ignoring the system standard set by the user!) we have to live with the fact, that these PDFs aren't displayed correctly for some of our customers and there's nothing we ca do against it. (Besides leaving all "non-standard" fonts out, of course...)

This review is for a previous version of the add-on (0.8.649). 

Langsam, Inkorrekt, Unbrauchbar Rated 1 out of 5 stars

ich muss diesen PDF reader mit meinem täglich gebrauchten reader evince vergleichen. Dabei fällt als erstes auf, dass dieser reader hier wesentlich langsamer ist die Seiten darzustellen. Nun ja gut ding will weile haben könnte man denken, aber nein, die Seiten werden auch noch falsch gerendert. Viele Zeichen sind in diesem reader komplett andere oder auch komplett verschwunden. Seit dieser reader in firefox eingebaut ist merke ich sogar wie Studenten von mir mit falsch ausgedruckten unterlagen ankommen und nicht wissen woher es kommt. Dieser PDF Viewer ist einfach nur ein fehler oder ein fehlgeschlagenes experiment pdf in JavaScript su rendern. Nicht verwenden.

This review is for a previous version of the add-on (0.8.649). 

Please file bugs at https://github.com/mozilla/pdf.js/issues

Poor visibility on some fonts Rated 2 out of 5 stars

This is a great concept - view a PDF file as a tabbed browser page - but this add-on does a poor job of rendering some fonts, resulting in a document that's difficult to read and thus requiring separate handling to open in Acrobat Reader in order to read the document. Needs more work.

This review is for a previous version of the add-on (0.8.649). 

Memory usage Rated 1 out of 5 stars

When i open a 500Ko PDF, and i scroll to the bottom, pdf.js uses 500Mo.
Fix it please ...

This review is for a previous version of the add-on (0.8.298). 

Rated 5 out of 5 stars

A true cross platform PDF viewer. *Thumbs up*

This review is for a previous version of the add-on (0.8.298).  This user has a previous review of this add-on.

Good, but some pages turn blank or black Rated 4 out of 5 stars

When I try to open pdf articles from journals, especially from opticsinfobase.org, it takes quite a bit of time, and the first displayed page is blank. Which means, I can't read the abstract and the introduction, two very important parts of a journal article paper.
Love the use of shortcuts otherwise, and could be a bit faster.

This review is for a previous version of the add-on (0.8.1). 

Cool, but not suitable for use ! Rated 1 out of 5 stars

Although this is an awesome achievement by Mozilla team this looks more like a lab demo project than something I would replace my PDF viewer.

I fill focus here in FF. There is no support for some smooth shadings, transp groups, overprint, bad accuracy, _very_ slow perf on complex files, no forms, annotations are either not supported or there is some problem on my files ...

You need to download the entire file before displaying anything.

I can drink my coffee before some files (magazines, brochures with lots of elements) render.... literally!

Mozilla implemented bunch of hacks in FF 20 to improve PDF support in FF (e.g. blend modes, new path fill rule, etc) but these are not available in IE and most other browsers

... forget the mobile unless you are dealing with tiny text only files pdf.js will exceed max memory for JS and browser will shut down.

This review is for a previous version of the add-on (0.8.1). 

Does what I need it to do Rated 5 out of 5 stars

Just installed and tested this add-on and it performed to my satisfaction. My needs are simple. I wanted three capabilities:
1. When I click on a .pdf on a website, I want the pdf displayed on my screen so I can decide what to do with it, not automatically saved to disk. Done.
2. When it's on my screen, I want the ability to print it right then and there. Done.
3. When it's on my screen, I want the ability to save it to my Download directory or just press on, if it's not the file I want. Done.
Nice little command bar format.

This review is for a previous version of the add-on (0.8.1). 

Rated 5 out of 5 stars

Нужный плагин, намного удобнее PDF читать, Спасибо!

This review is for a previous version of the add-on (0.8.1). 

Buggy! Screwed up all PDFs Rated 1 out of 5 stars

Not sure how I installed this. Guessing it piggybacked on some other program or something. Last few days i cannot open PDFs and just caught a glimpse of the title PDF.js as the PDF tried to open. Right now, all I get is a black screen. Useless. Can't download PDFs either..And worse of all, it isn't in the addons so I can't even disable it. If you google PDF.js, you'll see that many are having the same issues. Avoid like the plague.

This review is for a previous version of the add-on (0.8.1). 

Rated 5 out of 5 stars

Awesome add-on it's quick, doesn't lag, and organized very well.

5/5

This review is for a previous version of the add-on (0.8.1).