function LastMonth() {
	var now = new Date();
	var lastMonth = now.getMonth();		//先月
	
	if(lastMonth < 1){ lastMonth = lastMonth + 12;}
	
	document.write(lastMonth);
}


function ThisMonth() {
	var now = new Date();

	var thisMonth = now.getMonth() + 1;	//当月

	document.write(thisMonth);
}


function NextMonth() {
	var now = new Date();

	var nextMonth = now.getMonth() + 2;	//来月
	
	if(nextMonth > 12){ nextMonth = nextMonth - 12;}
	
	document.write(nextMonth);
}