Firefox 69: Full map is shown, but no markers.
Internet Explorer: Nothing except the +/- buttons in the upper left corner and the copyright link in the lower right corner.
Microsoft Edge: Same as the Internet Explorer, plus pink background, and a “x” at every tile and marker (but no map and no marker).
I tested this also with the original code from the wiki. On different PC with different internet access points. All are Windows 10 1903 64 Bit.
Is this because of some new security features? Is there a solution available?
If you look in the web console you’ll see the problem “Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at file:///C:/Temp/textfile.txt. (Reason: CORS request not http)”.