If you use extensions, it could be the Adblock apps, or you could be running two versions of java at the same time, or have is somehow disabled. I went through this last week.
Now and then I get problems with them and a couple of other sites. The current one with the article about possible reasons for Sherman testing positive.
I get a warning from my system they are running some additional version of Java Script and it could make my computer run slow. I just refuse to use it and all is well tho it affects the picture qualitys.
I am up to date with Java Script so its some extra deal they are doing at some sites methinks.
:les:
p.s. I turn my pop up blockers off for no one but Spokane County Library when I'm downloading books for my Kindle.