Unfortunately, it doesn't work like that anymore. Today I found that the website now sends (or tries to send) the label directly to your printer without using a Java applet. While it is true that many people probably don't have the required Java software on their computer to print the old way, the new way didn't work at all. I got a nice message saying the data had ben sent to the printer (it had not) nor could I confirm it printed okay.
What I thought was interesting was that when I clicked "no," all it said was to make sure I had Adobe Reader installed -- which of course I do (along with Apple's Preview and the full version of Acrobat). None of that seemed to help. The website offered no other information; they should have at least offered some things to check like their system requirements page, make sure the printer is turned on, etc. They offered nothing.
So I logged back in under FireFox and tried it there. The website again told me that the label had been sent to my printer and asked if it printed okay. Nope. However, a file called com.usps.cns.web.pdf.LabelGenerationServlet was downloaded to my Desktop. Of course, since 'LabelGenerationServlet' wasn't a file extension my Mac was familiar with, it gave up. So I renamed the file to com.usps.cns.web.pdf, and opened the file in Preview. Sure enough, there was my label. I manually hit Print and the label successfully came out of the printer.
Don't you just love it when people completely break functionality in an effort to make things better? Perhaps these hints will save someone else some trouble...

