unsigned long State;              
unsigned long lastState = LOW;    
unsigned long lastTimeforchange = 0;  
unsigned long debounceDelay = 10;     

void setup() {
  pinMode(8, INPUT_PULLUP);  
  pinMode(4, OUTPUT);     
  } 

void loop() {
  int Read = digitalRead(8); 

  if (Read != lastState) {
    lastTimeforchange = millis(); 
  }

  if ((millis() - lastTimeforchange) > debounceDelay) {
    if (Read != State) {
      State =Read; 
      if (State == HIGH) {
        digitalWrite(4, !digitalRead(4)); 
      }
    }
  }

  lastState = Read; 
}