let me google that for you .... https://www.virtualmin.com/node/5112
Thanks DeepDiver1975. I did as suggested in that article.
In Webmin opened Apache server > Domain docs.mobilecenter.lt > Mime Types > and then in TYPE pasted text/js and in EXTENSIONS .js > Saved > Restarted Apache, deleted Browser cache and refreshed page ... no luck at all same errors and can'l login
Refused to execute script from 'http://docs.mobilecenter.lt/core/vendor/jquery/dist/jquery.min.js?v=bf2c5b512afa46eaf9995aef9716bf98' because its MIME type ('text/js') is not executable, and strict MIME type checking is enabled.
By the way, installed Safari for windows and ... it works!!! But nor Chrome, Firefox, Opera or Edge are working.
You did enter text/js? text/javascript is the mimetype we are looking for.
but text/javascript ir listed in default Apache server Mime Types, should I reenter it once again for the domain?
And added text/javascript ... as I expected is same result - can't login.
As said above I have no idea about virtualmin - maybe you should try to find help in a virtualmin forum.
All I can say is: text/js is the wrong mimetype.
Sorry
but it is loading by script, not by server. By the way, as I mentioned there is one script that loads as text/javascript .. so, I think there is some problems with ownClound
When I logged in Safari I have message "There were problems with the code integrity check. More informationā¦" and the list of problems:
Transactional file locking should be configured to use memory-based locking, not the default slow database-based locking. See the documentation 
for more information.
Some files have not passed the integrity check. Further information on how to resolve this issue can be found in our documentation. (List of invalid filesā¦ / Rescanā¦)
You are accessing this site via HTTP. We strongly suggest you configure your server to require using HTTPS instead as described in our security tips.
No memory cache has been configured. To enhance your performance please configure a memcache if available. Further information can be found in our documentation.
No - because this one script is generated by the owncloud php code and we explicit set the correct content type. The content type for all other javascript files is determined by apache.
thanks, but I'm giving up. will look for less complicated and simpler script.
Or get a different server - this is the first time I facing such an issue.
Furthermore: any decent and security aware software will come up with the same issue.
Explicit mime type checking is a security feature modern browser have built in for a reason.
Anyway ... farewell.