The site is http://www.deserttrailshiking.com. Click the menu item “Hiking” on the right; on that page the menu on the right will now show three submenu items at the bottom. Click any one of them (eg ‘Dynamic Hike Schedule’ and see if you get the same error message that I do.

If you now return to the “Hiking” page, you’ll see that the link for those submenu items points to something like “www.deserttrailshiking.com/page13.php”. That PHP file contains the simple js script that I was referring to. It is not a virus and should not be identified as such.

To answer your next questions:

Windows 8.1
Asus Ultrabook
Waterfox (latest)
Avast! AV Free version (latest)

I’ve done complete system scans with Malwarebytes, and Avast and AdwCleaner over the last 24 hours.

Appreciate any help you can provide.