Arduino modified debounce

/*
 Debounce toggle

This code is in the public domain.

Original code at http://www.arduino.cc/en/Tutorial/Debounce

*/

const int buttonPin = 2;    // the number of the pushbutton pin
const int ledPin = 13;      // the number of the LED pin

int ledState = HIGH;         // the current state of the output pin
int buttonState;             // the current reading from the input pin
int lastButtonState = HIGH;  // the previous reading from the input pin
int isOn = 0;                // the current state of the LED

long lastDebounceTime = 0;  // the last time the output pin was toggled
long debounceDelay = 30;    // the debounce time; increase if the output flickers

void setup() {
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(ledPin, OUTPUT);
}

void loop() {
  // read the state of the switch into a local variable:
  int reading = digitalRead(buttonPin);

  // check to see if you just pressed the button
  // (i.e. the input went from LOW to HIGH),  and you've waited
  // long enough since the last press to ignore any noise:

  // If the switch changed, due to noise or pressing:
  if (reading != lastButtonState) {
    // reset the debouncing timer
    lastDebounceTime = millis();
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {
    // whatever the reading is at, it's been there for longer
    // than the debounce delay, so let's do our button action
    if(reading == LOW && isOn == 0) {          // Is the button in a pushed state and LED is off?
      do
      {
        digitalWrite(ledPin, HIGH);            // Turn it on
        isOn = 1;                              // and set the variable for the next go around
      } while(digitalRead(buttonPin) == LOW);  // Don't stop until we actually let go of the button
    }

    else if(reading == LOW && isOn == 1) {     // Is the button in a pushed state and LED is on?
      do
      {
        digitalWrite(ledPin, LOW);             // Turn it off
        isOn = 0;                              // set variable to off
      } while(digitalRead(buttonPin) == LOW);  // Don't stop until button is let go of
    }
  }
  // save the reading.  Next time through the loop,
  // it'll be the lastButtonState:
  lastButtonState = reading;
}