Loading URLs

/**
 * Loading URLs. 
 * 
 * Click on the button to open a URL in a browser.
 */

bool overButton = false;

void setup() {
    size(640, 360);
}

void draw() {
    background(204);

    if (overButton == true) {
        fill(255);
    } else {
        noFill();
    }

    rect(105, 60, 75, 75);

    line(135, 105, 155, 85);
    line(140, 85, 155, 85);
    line(155, 85, 155, 100);
}

void mousePressed() {
    if (overButton) {
        link("http://www.processing.org");
    }
}

void mouseMoved() {
    checkButtons();
}

void mouseDragged() {
    checkButtons();
}

void checkButtons() {
    if (mouseX > 105 && mouseX < 180 &&
        mouseY > 60 && mouseY < 135) {

        overButton = true;

    } else {
        overButton = false;
    }
}