Since you're on a Mac, you can make anything you can print into a PDF. Just hit File > Print from any application, including Firefox. The leftmost button is [PDF] which will save that to wherever you like.

Here's a screenshot of the print dialog box http://cl.ly/0h3O111W1k112f2q3X0Q

Yes, I have been doing what you suggested for years. My problem is that the latest 2 versions of Firefox show only a blank page -- nothing on it. Furthermore, all I can now print off the web are blank pages. I still can print from Safari, but had rarely used it before now and most of my bookmarks are on FireFox. My question would have been better put by asking why I only get blank pages when I attempt to print a webpage with the newest FireFox.

Try check Page Setup > Margins/Headers/Footers if one of the margins will be 25.0 instead of 0.25 or 50.0 instead of 0.50 etc.

thank you

Thanks for the tip. Although margins weren't the problem, the page length was. I had occasion to use my 500" long page and failed to change it back to US Letter size. I wouldn't have thought to pursue that avenue if not for your tip. Thanks!