This function encodes the string data to UTF-8, and returns the encoded version. UTF-8 is a standard mechanism used by Unicode for encoding wide character values into a byte stream. UTF-8 is transparent to plain ASCII characters, is self-synchronized (meaning it is possible for a program to figure out where in the bytestream characters start) and can be used with normal string comparison functions for sorting and such. PHP encodes UTF-8 characters in up to four bytes, like this:
Each b represents a bit that can be used to store character data.