PHP about the Static keyword

Static properties and methods can be called without instantiating the class, directly in the way they are used 类名::方法名 . Static properties do not allow an object to be called with an operator. In a static method, $this pseudo-variable is not allowed. You can use Self,parent,static to invoke static methods and properties internally.

Class Car {public    static $speed = ten;  Define a static property    //This is a public method of the common    function getspeed () {        return self:: $speed;  Get current Speed    }
This is a static method
public static function SpeedUp () {

        Return self:: $speed +=10;  Get acceleration Speed    }

Inherited:
Class Bigcar extends car{
public static function Start ()
{
Parent::speedup ();  Calling the parent class's method acceleration
　　　
}
}
Bigcar::start ();  static method acceleration for calling Bigcar
$car = new car ();
$car->getspeed ();  Call public method to get current speed
Car::speedup ();    Call the static method to get the acceleration

php about static keyword