Why is there an encoding error in php?

Question

PHP

In a php program, a string is obtained using the POST method. When outputting a string, a echo($product)normal Cyrillic string is displayed. But when outputting one character echo($product[0]), we get this �. I also noticed that it strlen($product)gives out the size twice the real one. What is the problem?

Answer 1

PHP does not have native support for utf-8, in which Cyrillic characters, for example, occupy two bytes. Use the functions from the mbstring extension.

Answer 2

Must use mb_** functions

Answer 3

Yes, you need to use mbstring, specifically for your case:
echo mb_substr($product, 0, 1);