Please see image given below:
I've put the code <meta http-equiv="refresh" content="5">
in the head section. Then I pressed Clt+Enter. The page is refresh after 5 second and my added code removed. (My intention was to refresh review page after every 5 second automatically).
Is it not possible to change the web code in client side permanently for client?
Can you explain, please?
No, you can't. Each time you refresh the page you pull it from the server so any local modification get lost.
If you need to refresh a page each X seconds you can use a browser addon like this