Because it has one of the worst UXs of any computing operation out there. Here’s what happens when it’s enabled in all browsers, PDF clients and OSes I’ve used:
- You click a PDF link
- Your entire browser page goes blank while the browser loads the PDF plugin and fetches the PDF
While the above is happening, there is NO progress indication whatsoever, mostly because browser and related internet app dev shops thought it was a good idea to eliminate the progress bar for UI simplicity. Yeah, maybe we should sell cars without speedometers too, but I digress. Because many PDF plugin UIs don’t load until the entire PDF file has been fetched, you could be staring a blank page while the browser churns away for an extended period of time if the PDF takes long to download. In Firefox – my browser of choice – tabs don’t run in separate processes, which means an in-browser PDF display episode could potentially crash the entire browser.*
Worse yet, at the end of the above process the PDF loads in a far less capable UI with less options than if it had loaded within a standalone PDF client. Even if you dodge all the above issues, you wind up with less usability and functionality
On the other hand, if you disable in-browser PDF display and simply download the file, here’s what happens
- Your browser’s download manager tells you how far along you are in downloading the file
- There’s no annoying wait for a PDF viewer plugin to load. The PDF client may take a while, but – on most multicore, 4+GB RAM machines – that won’t affect browser performance
- The PDF display process is handed off to your PDF client, which – due to the reduced number of variables compared to in-browser display – is probably a LOT better tested than the plugin anyway
Therefore, I thank NitroPDF, my PDF client of choice, for posting instructions on how to enable in-browser PDF display. Because now I can turn it OFF.
*Technically, since Firefox isolates plugins in separate processes, this shouldn’t happen. However, the blank page display and UI slowdown doesn’t inspire much confidence in browser power users such as myself. And no, I’m not switching to Chrome, Firefox 5 has a much better UI and is far more customizable.