14 DAY TRIAL // Firefox 12 is now installed on millions of computers and Firefox 13 Beta and Firefox 14 Aurora are ready for more adventurous users to test. As always, the most interesting release was Firefox 14 if only because it has the newest features and technology.
Still, even if Firefox 14 is packed with new stuff, there are a couple of things that didn't make the cut, that were deemed too experimental and unstable to even be included in Aurora.
The reason these features were not included and were pushed back to Firefox 15 is that the team didn't believe they could have them done by the time Firefox 14 was supposed to go stable, some 12 weeks from now.
The PDF.JS PDF viewer should land with Firefox 15
They're interesting features too, one thing that didn't make the cut is the built-in PDF viewer based on JavaScript. Mozilla has been working on the open-source viewer for a year now and, while included in the Firefox 14 Nightly, it was still not ready.
Pdf.js is similar to Chrome's PDF viewer but it is built entirely on web technologies, HTML, CSS3, JavaScript. This means that everything is rendered natively in the browser. This makes it fast and light and, most of all, secure – well, at least as secure as the browser running it.
What's more, it also means that any browser or any other project could use it to render PDF files, especially since it's open source.
The panel-based Download Manager has been pushed back as well
Another feature that didn't make the cut is also something that Mozilla's been working on for a very long time, namely the panel-based Download Manager. The feature was looking good, it's been working for a while now, but Mozilla decided at the last minute that it wasn't ready.
The panel download manager is actually present in Firefox 14 Aurora, but it's disabled by default. It's buggy, so you probably shouldn't depend on it, but if you want to see it in action go to about:config and set browser.download.useToolkitUI to "true."