I ran into a problem with a webpage that I'd made. When I accessed it, it
did not seem to work, and the console told me:

  Content Security Policy: The page's settings blocked the loading of a resource at inline ("default-src").

(To get to the console in Firefox, click the icon in the upper-right corner
that looks like 3 horizontal line segments, then "Web Developer" from the
drop-down menu, then "Web Console".)
What's worse is that when I looked to find a solution, it appeared that the
page itself was the problem. I tried a few things that did not work, before 
I realized that the same page worked well, when I accessed it from a 
different server. That is, I copied the code from one server to another. 
Loading it (from Firefox) from one server gave me this error.
Loading it (also from Firefox) from the other server did not give me this
error, and it worked fine. So it must be something on the server that is
causing this problem. Fortunately, I have the access to fix the problem
in the server.

On the server that hosts the page, the "/etc/httpd/conf/httpd.conf" file said:
  Header set Content-Security-Policy "default-src 'self';"

I changed it to say:
  Header set Content-Security-Policy "default-src 'self' script-src 'unsafe-inline';"

Now the script in the webpage works, at least partly. It still objected 
to the set.interval call. So I changed it again to:
  Header set Content-Security-Policy "default-src 'self' script-src 'unsafe-inline' 'unsafe-eval';"

and then it worked. 
-MCW, February 7, 2020

----------
Update:

The file works fine under Firefox. I got a report that someone was still
getting an error message, but has not been able to show me exactly what is
happening. I tried loading these files under Chrome, and it
admonished me with "The Content Security Policy directive 'default-src' contains 'script-src' as a source expression. Did you mean 'default-src ...; script-src...' (note the semicolon)?"
So I added a semi-colon to the line, as below:

[mweeks@gamedev conf]$ diff httpd_conf.good httpd.conf
362c362
< Header set Content-Security-Policy "default-src 'self' script-src 'unsafe-inline' 'unsafe-eval';"
---
> Header set Content-Security-Policy "default-src 'self'; script-src 'unsafe-inline' 'unsafe-eval';"
[mweeks@gamedev conf]$ 

I restarted the apache server, and still got this message after reloading the
test pages. Then I cleared all the cache from Chrome, shut it down, restarted
it, and it no longer gave me that error. The browser seemed to remember the
old .htaccess file even after the server's copy was changed, and even after
tha server was restarted,

Now it works, at least under FireFox and Chrome. 
-MCW
Wed Feb 26, 2020