Scope can be defined as the range of availability a variable has to the program in which it is declared. PHP variables can be one of four scope types:
The final type of variable scoping that I discuss is known as static. In contrast to the variables declared as function parameters, which are destroyed on the function's exit, a static variable will not lose its value when the function exits and will still hold that value should the function be called again.
You can declare a variable to be static simply by placing the keyword STATIC in front of the variable name.