// Przesuwanie kalendarza
function scroll_calendar(delta) {
	var style = getStyle(null, "pro-calendar-body", null); 
	var left = getStyle(null, "pro-calendar-body", "left");
	var width = getStyle(null, "pro-calendar-layer", "width");
	left = (typeof(left) == 'undefined' || typeof(left) == 'unknown') ? 1 : parseInt(left, 10); left += delta;
	width = (typeof(width) == 'undefined' || typeof(width) == 'unknown') ? 1 : parseInt(width, 10);
	if (left <= 0 && left + 2280 > width - 190) { // 2280 == szerokosc calego kalendarza, 190 == szerokosc jednego miesiaca
		if (style) style.left = left;
		if (delta > 0) --cal_month; else
		if (delta < 0) cal_month++;
		if (delta) cal_month = new String(cal_month);
	}
}