Setting time for changing class in javascript~!?(please help)

Question

Hi
how can i set time for changing style
i mean i need a javascript code which could change my class at night automatically
and then change the class for morning?
for iran,tehran time zone!
for example for night mode which websites use , but automatically:)
can anyone help?

Answer 1

https://code.sololearn.com/WS4n5j50RnIF/?ref=app

Answer 2

https://code.sololearn.com/WnLqMn9XJy7b/?ref=app

Answer 3

Thanks guys Calvin & Visph :) it's worked!