PHP strings are a series of bytes and do not contain any information about how those bytes should be translated to characters.
PHP stores the length of the string along with its contents and does not rely on a terminating character to denote the end of the string. This helps to make strings binary safe, as null characters in the string will not cause confusion.
On 32-bit systems a string can be as large as 2 GB. There is no particular limit on how long a string may be on a 64-bit PHP system.
In PHP, strings may be declared either as simple type or complex ...