What if I don't use <meta charset=UTF8>in my program.?

Answer 1

The default charset is UTF-8 so I think your going to be fine. I'm not sure though.

Answer 2

Most browsers will use utf-8 by default. But some may use another encoding which if it happens you will start seeing funny symbols instead of texts for some characters

Answer 3

if you do not put it in your site certain characters will not appear in the browser.

Answer 4

Its all about encoding and decoding. You may have problems after encoding