PHP Variable

The main way to store information in the middle of a PHP program is by using a variable.

•   All variables in PHP are denoted with a leading dollar sign ($). 
•   The value of a variable is the value of its most recent assignment. 
•   Variables are assigned with the = operator, with the variable on the left-hand side and the expression   to be evaluated on the right. 
•   Variables can, but do not need, to be declared before assignment. 
•   Variables in PHP do not have intrinsic types  -  a variable does not know in advance whether it will be used to store a number or a string of characters. 
•   Variables used before they are assigned have default values. 
•   PHP does a good job of automatically converting types from one to another when necessary. 
•   PHP variables are Perl-like.