how to make time widget in a blog?

Question

if i have a blog thats write about time zone comparison.
i use blogspot.
i want to make a css and javascript in my template as an external javascript.

and everytime i write about time zone comparison like
''time comparison in Tokyo and New York.''
i can show the current time of those cities
in my blog post.

can somebody help me!
and thanks you so much

Answer 1

https://www.zeitverschiebung.net/en/clock-widget