Strings on PHP

A string is series of characters, therefore, a character is the same as a byte. That is, there are exactly 256 different characters possible. This also implies that PHP has no native support of Unicode. See utf8_encode() and utf8_decode() for some basic Unicode functionality.
Note: It is no problem for a string to become very large. PHP imposes no boundary on the size of a string; the only limit is the available memory of the computer on which PHP is running.

Syntax
A string literal can be specified in four different ways:

single quoted
double quoted
heredoc …